What is the risk of irritable bowel syndrome after acute diverticulitis? How does diverticulitis impact the development of functional bowel disorders and mood disorders?

Diverticular Disease Burden and Chronic Symptoms

Diverticular disease imposes a significant burden on Western and industrialized societies. The prevalence of diverticulosis increases with age, affecting 70% of individuals aged 80 years or older in the United States. Up to 1 in 4 patients with diverticulosis experiences an inflammatory or infectious complication, such as diverticulitis, peritonitis, or abscess formation. These complications account for more than 300,000 hospital admissions, 1.5 million inpatient days, and $2.4 billion in direct costs annually in the United States.

Recent studies have reframed the paradigm of diverticular disease from an acute surgical illness to a chronic disorder with symptoms persisting long after acute complications subside. This form of symptomatic uncomplicated diverticular disease implies that chronic gastrointestinal symptoms co-occur with diverticulosis in the absence of overt complications or macroscopic inflammation.

Pathophysiologic Overlap Between Diverticular Disease and Irritable Bowel Syndrome

Research in symptomatic diverticular disease suggests a potential role for low-grade peridiverticular inflammation, altered motility reminiscent of “spastic colon,” diverticular-related visceral hypersensitivity, and altered intestinal microbiota in a pathophysiologic picture similar to irritable bowel syndrome (IBS).

Surveys have shown a concurrence between diverticulosis and IBS symptoms. In a cross-sectional survey of patients with colonic diverticular disease, 17% of diverticulosis subjects had frequent lower abdominal pain and 29% had altered bowel habits, rates significantly higher than nondiverticulosis controls. Another study found that 71% of patients experienced recurrent, long-standing abdominal pain after an attack, compared to only 34% of diverticular patients without an attack.

Increased Risk of IBS and Functional Bowel Disorders After Diverticulitis

The study aimed to investigate whether diverticulitis might lead to IBS and functional bowel disorders. The researchers performed a retrospective study of patients followed up for an average of 6.3 years at a Veteran’s Administration medical center. Patients with diverticulitis were identified and matched with patients without diverticulosis.

The results showed that patients with diverticulitis were 4.7-fold more likely to be diagnosed later with IBS, 2.4-fold more likely to be diagnosed later with a functional bowel disorder, and 2.2-fold more likely to develop a mood disorder, compared to controls.

Postdiverticulitis IBS: A New Disorder?

The researchers propose calling this disorder “postdiverticulitis IBS,” as it is similar to postinfectious IBS, where gastrointestinal disorders cause long-term symptoms. Diverticulitis appears to predispose patients to long-term gastrointestinal and emotional symptoms after resolution of inflammation.

Implications for the Management of Diverticular Disease

The findings suggest that patients with diverticulitis may be at risk for the development of IBS and functional bowel disorders, as well as mood disorders. This underscores the importance of considering the long-term consequences of diverticulitis and the need for a comprehensive approach to the management of diverticular disease.

Future Research Directions

Further research is needed to elucidate the underlying mechanisms connecting diverticulitis with the development of IBS and related disorders. Understanding these mechanisms could lead to improved prevention and management strategies for patients with diverticular disease.

Conclusion

In conclusion, this study provides important evidence that diverticulitis may be a risk factor for the development of IBS, functional bowel disorders, and mood disorders. The findings highlight the need for a more holistic approach to the management of diverticular disease, with a focus on long-term outcomes and the prevention of post-inflammatory sequelae.

Increased Risk for Irritable Bowel Syndrome After Acute Diverticulitis

Abstract

BACKGROUND & AIMS

Individuals with diverticulosis frequently also have irritable bowel syndrome (IBS), but there are no longitudinal data to associate acute diverticulitis with subsequent IBS, functional bowel disorders, or related emotional distress. In patients with postinfectious IBS, gastrointestinal disorders cause long-term symptoms, so we investigated whether diverticulitis might lead to IBS. We compared the incidence of IBS and functional bowel and related affective disorders among patients with diverticulitis.

METHODS

We performed a retrospective study of patients followed up for an average of 6.3 years at a Veteran’s Administration medical center. Patients with diverticulitis were identified based on International Classification of Diseases, 9th revision codes, selected for the analysis based on chart review (cases, n = 1102), and matched with patients without diverticulosis (controls, n = 1102). We excluded patients with prior IBS, functional bowel, or mood disorders. We then identified patients who were diagnosed with IBS or functional bowel disorders after the diverticulitis attack, and controls who developed these disorders during the study period. We also collected information on mood disorders, analyzed survival times, and calculated adjusted hazard ratios.

RESULTS

Cases were 4.7-fold more likely to be diagnosed later with IBS (95% confidence interval [CI], 1.6–14.0; P < .006), 2.4-fold more likely to be diagnosed later with a functional bowel disorder (95% CI, 1.6–3.6; P < .001), and 2.2-fold more likely to develop a mood disorder (CI, 1.4–3.5; P < .001) than controls.

CONCLUSIONS

Patients with diverticulitis could be at risk for later development of IBS and functional bowel disorders. We propose calling this disorder postdiverticulitis IBS. Diverticulitis appears to predispose patients to long-term gastrointestinal and emotional symptoms after resolution of inflammation; in this way, postdiverticulitis IBS is similar to postinfectious IBS.

Keywords: Outcome, Colon, Inflammatory Disorder, Functional Gastrointestinal Disease

Diverticular disease imposes a significant burden on Western and industrialized societies.^1,2 The prevalence of diverticulosis increases with age, affecting 70% of individuals aged 80 years or older in the United States.^1,2 Up to 1 in 4 patients with diverticulosis experiences an inflammatory or infectious complication, including diverticulitis, peritonitis, or abscess formation.^3,4 These complications account for more than 300,000 hospital admissions, 1.5 million inpatient days, and $2.4 billion in direct costs annually in the United States.^1,2,5 The prevalence of diverticular disease will increase with an aging and an expanding population.⁶

Although diverticular disease often is conceived as abrupt, disruptive, and comprising acute diverticulitis attacks surrounded by periods of clinical silence, this is not true for everyone. Recent studies have reframed the paradigm of diverticular disease from an acute surgical illness to a chronic disorder with symptoms persisting long after acute complications subside.^7–11 This form of symptomatic uncomplicated diverticular disease implies that chronic gastrointestinal symptoms co-occur with diverticulosis in the absence of overt complications or macroscopic inflammation.^7–11 Research in symptomatic diverticular disease suggests a potential role for low-grade peridiverticular inflammation.^9,12 Evolving research implicates altered motility reminiscent of “spastic colon,”¹³ diverticular-related visceral hypersensitivity,^9,14 and altered intestinal micro-biota¹⁵ in a pathophysiologic picture similar to irritable bowel syndrome (IBS), a condition marked by the same underlying mechanisms of inflammation,¹⁶ dysmotility,¹⁷ hyperalgesia,^18,19 and dysbiosis.²⁰

The pathophysiologic overlap between diverticular disease and IBS is supported by surveys showing concurrence between diverticulosis and IBS symptoms. In a cross-sectional survey of patients with colonic diverticular disease, Jung et al⁷ found that 17% of diverticulosis subjects had frequent lower abdominal pain and 29% had altered bowel habits, rates significantly higher than nondiverticulosis controls. Simpson et al¹⁰ found that 71% of patients experienced recurrent, long-standing abdominal pain after an attack vs only 34% of diverticular patients without an attack. Although these studies show important epidemiologic associations between diverticular disease and functional bowel symptoms, they cannot assert a temporal relationship. Beyond bowel symptoms, studies also have found that symptomatic diverticular disease is associated with diminished health-related quality of life, especially vitality and emotional health.^21,22 Taken together, these results indicate that diverticular disease may become a chronic illness marked by ongoing bowel symptoms and psychosocial distress. However, previous studies have been cross-sectional; it remains unknown whether the relationship between diverticular disease and IBS is causal, or merely associative.

To further explore the possibility of postdiverticulitis IBS (PDV-IBS), we conducted a longitudinal study comparing the risk of developing new IBS and related functional bowel diseases in diverticulitis cases vs controls. We bolstered these analyses by tracking new depression and mood disorders after the diverticulitis attack. We hypothesized that, as in postinfectious IBS (PI–IBS),²³ patients who experienced an acute diverticulitis attack would show a higher incidence of chronic bowel symptoms and psychosocial distress vs controls.

Methods

Data Source

To study the longitudinal relationship between acute diverticulitis and PDV-IBS, we performed a retrospective case vs control survival analysis using administrative and clinical data from the Veterans Affairs Greater Los Angeles Healthcare System (VAGLAHS). VAGLAHS maintains electronic medical records from 14 community clinics and 1 inpatient academic medical center: the West Los Angeles VA. The VAGLAHS database includes patient demographics, inpatient and outpatient treatment files, and laboratory, imaging, pathology, and pharmacy data.

Selection of Diverticulitis Cases

We queried the VAGLAHS database for inpatient or outpatient International Classification of Diseases, 9th revision (ICD-9) codes for diverticulitis and its complications, including diverticulitis (ICD-9 code: 562.11), diverticular abscesses (ICD-9 code: 569.5), and diverticular perforations (ICD-9 code: 569.83). We performed diagnostic coding corroboration through medical record review. Physician abstractors used a standardized chart review including automated natural language searching of provider notes for relevant keywords (eg, “diverticulitis,” “diverticular disease”), and assessment of laboratory, imaging, and pathology records. For inclusion, we required a formal chart diagnosis of diverticulitis by a treating physician, based on clinical parameters (eg, leukocytosis, fever), and/or radiographic or surgical specimens. We categorized each case based on the clinical level of evidence used to make the diagnosis. Clinical assessment and laboratory data were assigned lower levels of evidence, whereas computed tomography (CT) or surgically confirmed cases were assigned the highest levels of evidence. All cases received a course of oral or parenteral antibiotics.

We excluded cases in which a chart review failed to identify a physician diagnosis based on clinical parameters. In addition, we excluded subjects with pre-existing diagnoses suggesting a history of gastrointestinal symptoms before the diverticulitis index date. Specifically, we excluded patients with pre-existing diagnostic codes for IBS (ICD-9 code: 564.1) and related functional bowel disease diagnoses including spastic colon, functional diarrhea, constipation, and abdominal pain (ICD-9 codes: 564.X, 789.X, and 306.4). Moreover, because psychiatric disease has been known to be a risk factor for IBS, we also excluded patients with ICD-9 codes 296.2 (major depressive disorder) and 300.4 (dysthymic disorder) and related variants. The purpose of these exclusions was to focus our analysis on new IBS diagnoses after the index attack.

We further excluded patients with codes for other gastrointestinal disorders, including peptic ulcer disease, inflammatory bowel disease, and gastrointestinal malignancies. The purpose of these exclusions was to ensure the outcome of interest (new IBS diagnoses) was valid because these exclusionary diagnoses are either incompatible with or undermine the diagnosis of IBS.

Selection of Controls

For each diverticulitis case, we identified an age (±1 y), sex, and inpatient vs outpatient-matched control who sought care on the same day as the diverticulitis case, but who did not have a diverticulitis code. We randomly selected controls through incidence density sampling with replacement. On chart review, controls that did not meet the clinical assessment of diverticulitis were included.

Outcomes

Primary outcome: postdiverticulitis irritable bowel syndrome

The primary outcome was a new IBS diagnosis after the index diverticulitis attack (for cases) or enrollment date (for controls). We defined IBS as acquisition of ICD-9 code 564.1. To validate IBS diagnoses, we conducted a manual chart audit of all subjects who acquired the IBS code during the observation period. We performed a review of progress notes, prescription records, and endoscopy, surgery, radiology, microbiology, and pathology reports for each subject during the 12 months before and after the ICD-9 code was assigned. Previously identified criteria for IBS have been developed.²⁴ In practice, IBS is diagnosed using the Rome criteria²⁵: a case-finding definition designed for clinical trials rather than retrospective chart reviews. Given the limitations of relying on database records, we used pragmatic modified criteria incorporating Rome and administrative definitions.

We made a chart-confirmed diagnosis of IBS if the patient: (1) showed no clinical or objective evidence of organic intestinal pathology, including malignancy, inflammatory bowel disease, gastrointestinal infection, or celiac sprue; (2) showed no alarm signs or symptoms, including unintended weight loss, gastrointestinal bleeding, or evidence of anemia; and (3) reported symptoms consistent with Rome criteria for IBS, including both recurrent abdominal pain or discomfort and repeated defecatory symptoms, including constipation or diarrhea, for a minimum duration of 6 months. We applied these criteria to all ICD-9 –positive instances of IBS. To further validate IBS diagnoses, we pulled a 20% random sample of subjects without an IBS ICD-9 code and sought evidence for IBS from chart review. After stratifying coded and chart-confirmed diagnoses, we calculated the sensitivity, specificity, and positive and negative predictive values for the ICD-9 IBS code in our population.

Secondary outcomes

In addition to new IBS diagnoses, we also tracked acquisition of ICD-9 codes for related functional bowel diseases including spastic colon, functional diarrhea, constipation, and abdominal pain (ICD-9 codes: 564.X, 789.X, and 306.4). Finally, in light of data that diverticulitis can trigger long-term decrements in emotional health,^21,22 we measured new diagnoses of depression and related mood disorders (ICD-9 series: 296.XX).

Statistical Analyses and Power Calculation

We generated frequencies for baseline population characteristics, and compared these values using chi-square testing for numeric variables, and Student t tests for continuous variables. We then performed time-to-event survival analyses with right censoring if subjects: (1) developed IBS; (2) died; (3) were lost to follow-up evaluation; or (4) or were still present by the end of the follow-up period (January 1, 2012). We then performed a Cox proportional hazards model adjusting for age, race, ethnicity, sex, inpatient vs outpatient status, and comorbidity, as measured by the Deyo adaptation of the Charlson comorbidity score.²⁶ We tested the proportional-hazards assumption and used the likelihood-ratio test in the Cox models to evaluate the significance of the observed differences in survival functions between cases and controls. To power a model with 10 potential independent variables, we required a minimum of 20 observations per variable, or 200 subjects, to test the independent relationship between diverticulitis exposure and IBS. In all tests, we considered a P value of less than .05 significant. We performed statistical analyses with SAS Statistical Software, version 9. 2 (SAS Institute, Cary, NC). The VAG-LAHS institutional review board approved this study (Project Coordinating Center #0016).

Results

Patient Characteristics and Descriptive Statistics

We found 3992 patients with ICD-9 codes for diverticular disease and 1105 had chart-confirmed diverticulitis. Of those with diverticulitis, a subset of 326 were diagnosed based on either CT or surgical confirmation. An equal number of age, sex, and inpatient vs outpatient matched controls were selected randomly. provides key characteristics of the sample. Cases and controls were distributed similarly along demographic variables. The mean follow-up period was 6.3 years (median, 3.4 y; range, 0.3–9.0 y).

Table 1

Variable	Diverticulitis cases (n ± 1102)	Matched controls (n ± 1102)
Mean age, y	62. 2 ± 12.5	62.2 ± 13
Sex, % male	95.6	95.6
Race/ethnicity
White	38.2%	46.9%
Black	21.2%	11.1%
Hispanic	6.6%	8.4%
Other or missinga	34. 0%	33.6%
Charlson comorbidity score	1.5 ± 2.1	1.1 ± 1.8
Person-years of follow-up evaluation	7051	6935

Validity of Primary Outcome

There were 24 cases of newly diagnosed IBS during the study period: 20 in cases, and 4 in controls. Chart review confirmed that 23 of the 24 cases met prespecified diagnostic criteria. The subsequent analyses excluded the false case. Among 240 subjects from the validation cohort without an IBS ICD-9 code, only 1 subject met criteria for IBS. This yielded an IBS code sensitivity, specificity, positive predictive value, and negative predictive value of 95. 8%, 99.2%, 92%, and 99.6%, respectively.

Irritable Bowel Syndrome in Cases vs Controls

presents survival curves extending out 9 years for incident IBS diagnoses in diverticulitis cases vs matched controls. In unadjusted survival analysis, cases were 4.6 times more likely to acquire an IBS code during the observation period vs controls (hazard ratio [HR], 4.6; 95% confidence intervals [CI], 1.6 –13.6; P = .005). After adjusting for age, sex, ethnicity, race, inpatient vs outpatient status, and comorbidity score the cases remained more likely to receive an IBS code (HR, 4.7; 95% CI, 1.6 –14.0; P = .006).

Incidence of new IBS diagnoses in diverticulitis cases vs matched controls.

Secondary Outcomes in Cases vs Controls

presents survival curves for new functional gastrointestinal disorder codes in diverticulitis cases vs controls. There were 146 new functional gastrointestinal diagnoses: 95 in cases, 51 in controls. Cases were 2.3 times more likely to receive any functional bowel disorder code vs controls (HR, 2. 3; 95% CI, 1.6 –3.3; P < .001). This difference remained significant after adjustment for covariates (HR, 2.4; 95% CI, 1.6 –3.6; P < .001). presents the curves for a new diagnosis of depression and related mood disorders. When focusing on the cases confirmed by either CT or surgical resection, there were 12 new diagnoses of functional gastrointestinal disorder codes: 11 in cases, 1 in controls; the difference remained highly significant (HR, 11.7; 95% CI, 1.5–246; P = .005). There were 98 new diagnoses of mood-disorder diagnoses: 63 in cases, 35 in controls. Cases remained more likely to acquire a mood disorder diagnosis vs controls in both unadjusted (HR, 1.9; 95% CI, 1.2–3.0; P = .007) and adjusted (HR, 2.2; 95% CI, 1.4 –3.6; P < .001) analyses.

Incidence of new functional bowel disorder diagnoses in diverticulitis cases vs matched controls.

Incidence of new depression and mood disorder diagnoses in diverticulitis cases vs matched controls.

Discussion

Previous research documented an association between diverticular disease and chronic gastrointestinal symptoms.^7,10,11 Because these studies were cross-sectional, it remains unclear whether the relationship between conditions is causal or merely associative. We conducted a longitudinal analysis comparing new IBS and functional bowel diagnoses in a large sample of chart-confirmed diverticulitis cases vs controls. After excluding patients with pre-existing IBS or functional bowel diagnoses, we found that diverticulitis patients were 4.7 and 2.4 times more likely than controls to be diagnosed with IBS or a functional bowel disorder, respectively, after experiencing their attack.

It is possible that diverticulitis patients in this study were simply misdiagnosed as having IBS, or vice versa. However, 3 observations undermine this assertion. First, we excluded patients with pre-existing IBS and functional bowel diagnoses. The high background prevalence of IBS in Western populations confounds previous work on the natural history of diverticular disease. We then found a higher incidence of new diagnoses in chart-confirmed diverticulitis cases vs matched controls. This temporal relationship suggests that the IBS and functional bowel diagnoses followed the index attack, and not the other way around. Moreover, if we adopt the null hypothesis, we would expect no systematic differences in the reporting of any long-term functional symptoms between cases and controls. Although ICD-9 codes can be an insensitive diagnostic appraisal of IBS or diverticulitis, cases were confirmed by extensive physician chart review. The strength of our diagnostic validation process, as measured by traditional test metrics, bolsters this view. Nonetheless, this study was retrospective, so it remains impossible to definitively confirm the relationship.

Second, reveals that the curves did not fully diverge until 10 months after the index enrollment dates and persisted for months after, whereas rates for the controls plateaued. Chronic abdominal pain and persistent alterations in bowel habits—the hallmarks of the Rome criteria for IBS—are atypical for the usually short-lived functional abdominal pain that can accompany acute diverticular attacks. This suggests that IBS was not simply diagnosed in and around the time of the diverticulitis attack, but was identified in the months and years after. Although this, too, cannot prove a causal link between diverticulitis and subsequent IBS, it provides further evidence that diverticulitis may have preceded IBS, and not vice versa. It further argues against a misclassification at the time of the index attack because one might expect new IBS diagnoses to occur closer to the index date in the case of misclassification, not in the months and years to follow.

Third, we supported these bowel symptom analyses by evaluating a related yet very different outcome—incident depression and related mood disorders. Because chronic bowel disorders are associated with depression, especially IBS,²⁷ we hypothesized that diverticulitis cases would have a higher incidence of affective diagnoses vs matched controls; shows this finding. Coupled with finding a higher incidence of long-term chart-confirmed IBS and functional bowel diagnoses in cases vs controls, these results support the hypothesis that diverticulitis might trigger long-term physical and emotional symptoms well beyond the acute event.

The development of PDV-IBS is biologically plausible. Research has shown potentially shared pathophysiologic mechanisms between IBS and symptomatic diverticular disease. There are reports that some IBS patients show low-grade colonic inflammation in the absence of macroscopic colitis.⁵ Moreover, inflammation may alter gastrointestinal reflexes, amplify visceral sensitivity, render the bowel more susceptible to negative effects of microbiota, and alter motility in IBS.⁵ Similarly, some small studies have shown chronic microscopic inflammation in biopsy specimens taken from within and around diverticula in patients with symptomatic diverticular disease.^12,28,29 Similar to IBS, patients with diverticular disease have heightened visceral pain perception in response to luminal distension compared with controls.^8,14 Another putative mechanism of chronic diverticular disease involves shifts in intestinal microbiota leading to chronic inflammation, similar to theoretical models for IBS. ²⁰ Several lines of evidence support a potential association between the intestinal microbiota and diverticular disease. Gut-directed antibiotics may reduce attacks of recurrent diverticulitis and treat gastrointestinal symptoms in patients with symptomatic diverticular disease^29,30; data also have shown modest benefits of antibiotics in IBS.³¹ Low dietary fiber intake, a putative risk factor for chronic diverticular disease and IBS with constipation, is also associated with alterations in the gut microbial composition³²; these changes might lead to bacterial overgrowth or even precipitate acute diverticulitis.¹² In a study of 90 patients with a history of acute diverticulitis, 60% met criteria for small intestinal bacterial overgrowth,¹⁵ a condition also purported to occur in many patients with IBS.²⁰ Finally, there is a strong and consistent link between acute bacterial gastroenteritis and PI–IBS,²³ a condition in which chronic bowel symptoms persist long after the infectious agent has cleared. Analogous to the postinflammatory model of PI–IBS, it is possible that acute diverticular inflammation may trigger PDV-IBS.

This study had several limitations. First, although we performed a longitudinal analysis, we cannot assert that diverticulitis caused IBS in this study. Although this study suggests directionality from diverticulitis to IBS, only a large prospective study can answer this question definitively. In the meantime, there is biological plausibility of a link, cross-sectional evidence from multiple previous studies, and now longitudinal evidence of a temporal relationship between diverticulitis and IBS. Second, we relied on administrative data to identify diverticulitis cases. These codes could have been applied inaccurately, and true cases may have been missed altogether. In fact, the diagnosis of diverticulitis in everyday clinical practice is often difficult because leukocytosis is not a requirement for diagnosis and CT scanning is not always performed. Thus, we used a pragmatic definition based on the same everyday clinical decisions made by providers on the front lines. However, when focusing just on those subjects with CT or surgically confirmed diverticulitis, the difference in new functional gastrointestinal diagnoses remained highly statistically significant. Future studies may better standardize the definition of diverticulitis in a prospective protocol. Last, our overall rate of IBS in this series was less than 1%; this is considerably lower than the 7% population prevalence quoted in IBS guidelines.³³ However, IBS is generally more prevalent in younger women, and this series consisted almost entirely of men with an average age of 62 years. We also excluded pre-existing diagnoses of IBS, used the more restrictive Rome criteria, and solely focused on new diagnoses during the study period— generally rare diagnosis to accumulate de novo after the age of 60 in men.

Our findings support the evolving paradigm of diverticular disease as a chronic illness, not merely an acute condition marked by abrupt complications. Far from a self-limited episode, acute diverticulitis may become a chronic disorder in some patients. Diverticulitis is correlated with not only chronic IBS symptoms but also long-term emotional distress beyond the event itself. Awareness of this possible risk is important because persistent, untreated gastrointestinal symptoms and comorbid depression may worsen outcomes and increase the economic burden of an already prevalent disease. Existing diverticulitis guidelines largely focus on acute management principles rather than chronic symptoms.^4,34 However, enhanced awareness of the potential long-term impact of diverticulitis, including the possibility of PDV-IBS, may allow for more timely diagnosis and treatment. Future research should identify demographic and clinical predictors of PDV-IBS and evaluate its incidence in prospective studies to better determine whether this link is causal or merely associative.

Increased Risk for Irritable Bowel Syndrome After Acute Diverticulitis

Abstract

BACKGROUND & AIMS

Individuals with diverticulosis frequently also have irritable bowel syndrome (IBS), but there are no longitudinal data to associate acute diverticulitis with subsequent IBS, functional bowel disorders, or related emotional distress. In patients with postinfectious IBS, gastrointestinal disorders cause long-term symptoms, so we investigated whether diverticulitis might lead to IBS. We compared the incidence of IBS and functional bowel and related affective disorders among patients with diverticulitis.

METHODS

We performed a retrospective study of patients followed up for an average of 6.3 years at a Veteran’s Administration medical center. Patients with diverticulitis were identified based on International Classification of Diseases, 9th revision codes, selected for the analysis based on chart review (cases, n = 1102), and matched with patients without diverticulosis (controls, n = 1102). We excluded patients with prior IBS, functional bowel, or mood disorders. We then identified patients who were diagnosed with IBS or functional bowel disorders after the diverticulitis attack, and controls who developed these disorders during the study period. We also collected information on mood disorders, analyzed survival times, and calculated adjusted hazard ratios.

RESULTS

Cases were 4.7-fold more likely to be diagnosed later with IBS (95% confidence interval [CI], 1.6–14.0; P < .006), 2.4-fold more likely to be diagnosed later with a functional bowel disorder (95% CI, 1.6–3.6; P < .001), and 2.2-fold more likely to develop a mood disorder (CI, 1.4–3.5; P < .001) than controls.

CONCLUSIONS

Patients with diverticulitis could be at risk for later development of IBS and functional bowel disorders. We propose calling this disorder postdiverticulitis IBS. Diverticulitis appears to predispose patients to long-term gastrointestinal and emotional symptoms after resolution of inflammation; in this way, postdiverticulitis IBS is similar to postinfectious IBS.

Keywords: Outcome, Colon, Inflammatory Disorder, Functional Gastrointestinal Disease

Diverticular disease imposes a significant burden on Western and industrialized societies.^1,2 The prevalence of diverticulosis increases with age, affecting 70% of individuals aged 80 years or older in the United States. ^1,2 Up to 1 in 4 patients with diverticulosis experiences an inflammatory or infectious complication, including diverticulitis, peritonitis, or abscess formation.^3,4 These complications account for more than 300,000 hospital admissions, 1.5 million inpatient days, and $2.4 billion in direct costs annually in the United States.^1,2,5 The prevalence of diverticular disease will increase with an aging and an expanding population.⁶

Although diverticular disease often is conceived as abrupt, disruptive, and comprising acute diverticulitis attacks surrounded by periods of clinical silence, this is not true for everyone. Recent studies have reframed the paradigm of diverticular disease from an acute surgical illness to a chronic disorder with symptoms persisting long after acute complications subside.^7–11 This form of symptomatic uncomplicated diverticular disease implies that chronic gastrointestinal symptoms co-occur with diverticulosis in the absence of overt complications or macroscopic inflammation. ^7–11 Research in symptomatic diverticular disease suggests a potential role for low-grade peridiverticular inflammation.^9,12 Evolving research implicates altered motility reminiscent of “spastic colon,”¹³ diverticular-related visceral hypersensitivity,^9,14 and altered intestinal micro-biota¹⁵ in a pathophysiologic picture similar to irritable bowel syndrome (IBS), a condition marked by the same underlying mechanisms of inflammation,¹⁶ dysmotility,¹⁷ hyperalgesia,^18,19 and dysbiosis.²⁰

The pathophysiologic overlap between diverticular disease and IBS is supported by surveys showing concurrence between diverticulosis and IBS symptoms. In a cross-sectional survey of patients with colonic diverticular disease, Jung et al⁷ found that 17% of diverticulosis subjects had frequent lower abdominal pain and 29% had altered bowel habits, rates significantly higher than nondiverticulosis controls. Simpson et al¹⁰ found that 71% of patients experienced recurrent, long-standing abdominal pain after an attack vs only 34% of diverticular patients without an attack. Although these studies show important epidemiologic associations between diverticular disease and functional bowel symptoms, they cannot assert a temporal relationship. Beyond bowel symptoms, studies also have found that symptomatic diverticular disease is associated with diminished health-related quality of life, especially vitality and emotional health.^21,22 Taken together, these results indicate that diverticular disease may become a chronic illness marked by ongoing bowel symptoms and psychosocial distress. However, previous studies have been cross-sectional; it remains unknown whether the relationship between diverticular disease and IBS is causal, or merely associative.

To further explore the possibility of postdiverticulitis IBS (PDV-IBS), we conducted a longitudinal study comparing the risk of developing new IBS and related functional bowel diseases in diverticulitis cases vs controls. We bolstered these analyses by tracking new depression and mood disorders after the diverticulitis attack. We hypothesized that, as in postinfectious IBS (PI–IBS),²³ patients who experienced an acute diverticulitis attack would show a higher incidence of chronic bowel symptoms and psychosocial distress vs controls.

Methods

Data Source

To study the longitudinal relationship between acute diverticulitis and PDV-IBS, we performed a retrospective case vs control survival analysis using administrative and clinical data from the Veterans Affairs Greater Los Angeles Healthcare System (VAGLAHS). VAGLAHS maintains electronic medical records from 14 community clinics and 1 inpatient academic medical center: the West Los Angeles VA. The VAGLAHS database includes patient demographics, inpatient and outpatient treatment files, and laboratory, imaging, pathology, and pharmacy data.

Selection of Diverticulitis Cases

We queried the VAGLAHS database for inpatient or outpatient International Classification of Diseases, 9th revision (ICD-9) codes for diverticulitis and its complications, including diverticulitis (ICD-9 code: 562.11), diverticular abscesses (ICD-9 code: 569.5), and diverticular perforations (ICD-9 code: 569.83). We performed diagnostic coding corroboration through medical record review. Physician abstractors used a standardized chart review including automated natural language searching of provider notes for relevant keywords (eg, “diverticulitis,” “diverticular disease”), and assessment of laboratory, imaging, and pathology records. For inclusion, we required a formal chart diagnosis of diverticulitis by a treating physician, based on clinical parameters (eg, leukocytosis, fever), and/or radiographic or surgical specimens. We categorized each case based on the clinical level of evidence used to make the diagnosis. Clinical assessment and laboratory data were assigned lower levels of evidence, whereas computed tomography (CT) or surgically confirmed cases were assigned the highest levels of evidence. All cases received a course of oral or parenteral antibiotics.

We excluded cases in which a chart review failed to identify a physician diagnosis based on clinical parameters. In addition, we excluded subjects with pre-existing diagnoses suggesting a history of gastrointestinal symptoms before the diverticulitis index date. Specifically, we excluded patients with pre-existing diagnostic codes for IBS (ICD-9 code: 564.1) and related functional bowel disease diagnoses including spastic colon, functional diarrhea, constipation, and abdominal pain (ICD-9 codes: 564.X, 789.X, and 306.4). Moreover, because psychiatric disease has been known to be a risk factor for IBS, we also excluded patients with ICD-9 codes 296.2 (major depressive disorder) and 300.4 (dysthymic disorder) and related variants. The purpose of these exclusions was to focus our analysis on new IBS diagnoses after the index attack.

We further excluded patients with codes for other gastrointestinal disorders, including peptic ulcer disease, inflammatory bowel disease, and gastrointestinal malignancies. The purpose of these exclusions was to ensure the outcome of interest (new IBS diagnoses) was valid because these exclusionary diagnoses are either incompatible with or undermine the diagnosis of IBS.

Selection of Controls

For each diverticulitis case, we identified an age (±1 y), sex, and inpatient vs outpatient-matched control who sought care on the same day as the diverticulitis case, but who did not have a diverticulitis code. We randomly selected controls through incidence density sampling with replacement. On chart review, controls that did not meet the clinical assessment of diverticulitis were included.

Outcomes

Primary outcome: postdiverticulitis irritable bowel syndrome

The primary outcome was a new IBS diagnosis after the index diverticulitis attack (for cases) or enrollment date (for controls). We defined IBS as acquisition of ICD-9 code 564.1. To validate IBS diagnoses, we conducted a manual chart audit of all subjects who acquired the IBS code during the observation period. We performed a review of progress notes, prescription records, and endoscopy, surgery, radiology, microbiology, and pathology reports for each subject during the 12 months before and after the ICD-9 code was assigned. Previously identified criteria for IBS have been developed.²⁴ In practice, IBS is diagnosed using the Rome criteria²⁵: a case-finding definition designed for clinical trials rather than retrospective chart reviews. Given the limitations of relying on database records, we used pragmatic modified criteria incorporating Rome and administrative definitions.

We made a chart-confirmed diagnosis of IBS if the patient: (1) showed no clinical or objective evidence of organic intestinal pathology, including malignancy, inflammatory bowel disease, gastrointestinal infection, or celiac sprue; (2) showed no alarm signs or symptoms, including unintended weight loss, gastrointestinal bleeding, or evidence of anemia; and (3) reported symptoms consistent with Rome criteria for IBS, including both recurrent abdominal pain or discomfort and repeated defecatory symptoms, including constipation or diarrhea, for a minimum duration of 6 months. We applied these criteria to all ICD-9 –positive instances of IBS. To further validate IBS diagnoses, we pulled a 20% random sample of subjects without an IBS ICD-9 code and sought evidence for IBS from chart review. After stratifying coded and chart-confirmed diagnoses, we calculated the sensitivity, specificity, and positive and negative predictive values for the ICD-9 IBS code in our population.

Secondary outcomes

In addition to new IBS diagnoses, we also tracked acquisition of ICD-9 codes for related functional bowel diseases including spastic colon, functional diarrhea, constipation, and abdominal pain (ICD-9 codes: 564.X, 789.X, and 306.4). Finally, in light of data that diverticulitis can trigger long-term decrements in emotional health,^21,22 we measured new diagnoses of depression and related mood disorders (ICD-9 series: 296.XX).

Statistical Analyses and Power Calculation

We generated frequencies for baseline population characteristics, and compared these values using chi-square testing for numeric variables, and Student t tests for continuous variables. We then performed time-to-event survival analyses with right censoring if subjects: (1) developed IBS; (2) died; (3) were lost to follow-up evaluation; or (4) or were still present by the end of the follow-up period (January 1, 2012). We then performed a Cox proportional hazards model adjusting for age, race, ethnicity, sex, inpatient vs outpatient status, and comorbidity, as measured by the Deyo adaptation of the Charlson comorbidity score.²⁶ We tested the proportional-hazards assumption and used the likelihood-ratio test in the Cox models to evaluate the significance of the observed differences in survival functions between cases and controls. To power a model with 10 potential independent variables, we required a minimum of 20 observations per variable, or 200 subjects, to test the independent relationship between diverticulitis exposure and IBS. In all tests, we considered a P value of less than .05 significant. We performed statistical analyses with SAS Statistical Software, version 9.2 (SAS Institute, Cary, NC). The VAG-LAHS institutional review board approved this study (Project Coordinating Center #0016).

Results

Patient Characteristics and Descriptive Statistics

We found 3992 patients with ICD-9 codes for diverticular disease and 1105 had chart-confirmed diverticulitis. Of those with diverticulitis, a subset of 326 were diagnosed based on either CT or surgical confirmation. An equal number of age, sex, and inpatient vs outpatient matched controls were selected randomly. provides key characteristics of the sample. Cases and controls were distributed similarly along demographic variables. The mean follow-up period was 6.3 years (median, 3.4 y; range, 0.3–9.0 y).

Table 1

Validity of Primary Outcome

There were 24 cases of newly diagnosed IBS during the study period: 20 in cases, and 4 in controls. Chart review confirmed that 23 of the 24 cases met prespecified diagnostic criteria. The subsequent analyses excluded the false case. Among 240 subjects from the validation cohort without an IBS ICD-9 code, only 1 subject met criteria for IBS. This yielded an IBS code sensitivity, specificity, positive predictive value, and negative predictive value of 95.8%, 99.2%, 92%, and 99.6%, respectively.

Irritable Bowel Syndrome in Cases vs Controls

presents survival curves extending out 9 years for incident IBS diagnoses in diverticulitis cases vs matched controls. In unadjusted survival analysis, cases were 4.6 times more likely to acquire an IBS code during the observation period vs controls (hazard ratio [HR], 4.6; 95% confidence intervals [CI], 1.6 –13.6; P = .005). After adjusting for age, sex, ethnicity, race, inpatient vs outpatient status, and comorbidity score the cases remained more likely to receive an IBS code (HR, 4.7; 95% CI, 1.6 –14.0; P = .006).

Incidence of new IBS diagnoses in diverticulitis cases vs matched controls.

Secondary Outcomes in Cases vs Controls

presents survival curves for new functional gastrointestinal disorder codes in diverticulitis cases vs controls. There were 146 new functional gastrointestinal diagnoses: 95 in cases, 51 in controls. Cases were 2.3 times more likely to receive any functional bowel disorder code vs controls (HR, 2.3; 95% CI, 1.6 –3.3; P < .001). This difference remained significant after adjustment for covariates (HR, 2.4; 95% CI, 1.6 –3.6; P < .001). presents the curves for a new diagnosis of depression and related mood disorders. When focusing on the cases confirmed by either CT or surgical resection, there were 12 new diagnoses of functional gastrointestinal disorder codes: 11 in cases, 1 in controls; the difference remained highly significant (HR, 11.7; 95% CI, 1.5–246; P = .005). There were 98 new diagnoses of mood-disorder diagnoses: 63 in cases, 35 in controls. Cases remained more likely to acquire a mood disorder diagnosis vs controls in both unadjusted (HR, 1.9; 95% CI, 1.2–3.0; P = .007) and adjusted (HR, 2.2; 95% CI, 1.4 –3.6; P < .001) analyses.

Incidence of new functional bowel disorder diagnoses in diverticulitis cases vs matched controls.

Incidence of new depression and mood disorder diagnoses in diverticulitis cases vs matched controls.

Discussion

Previous research documented an association between diverticular disease and chronic gastrointestinal symptoms.^7,10,11 Because these studies were cross-sectional, it remains unclear whether the relationship between conditions is causal or merely associative. We conducted a longitudinal analysis comparing new IBS and functional bowel diagnoses in a large sample of chart-confirmed diverticulitis cases vs controls. After excluding patients with pre-existing IBS or functional bowel diagnoses, we found that diverticulitis patients were 4.7 and 2.4 times more likely than controls to be diagnosed with IBS or a functional bowel disorder, respectively, after experiencing their attack.

It is possible that diverticulitis patients in this study were simply misdiagnosed as having IBS, or vice versa. However, 3 observations undermine this assertion. First, we excluded patients with pre-existing IBS and functional bowel diagnoses. The high background prevalence of IBS in Western populations confounds previous work on the natural history of diverticular disease. We then found a higher incidence of new diagnoses in chart-confirmed diverticulitis cases vs matched controls. This temporal relationship suggests that the IBS and functional bowel diagnoses followed the index attack, and not the other way around. Moreover, if we adopt the null hypothesis, we would expect no systematic differences in the reporting of any long-term functional symptoms between cases and controls. Although ICD-9 codes can be an insensitive diagnostic appraisal of IBS or diverticulitis, cases were confirmed by extensive physician chart review. The strength of our diagnostic validation process, as measured by traditional test metrics, bolsters this view. Nonetheless, this study was retrospective, so it remains impossible to definitively confirm the relationship.

Second, reveals that the curves did not fully diverge until 10 months after the index enrollment dates and persisted for months after, whereas rates for the controls plateaued. Chronic abdominal pain and persistent alterations in bowel habits—the hallmarks of the Rome criteria for IBS—are atypical for the usually short-lived functional abdominal pain that can accompany acute diverticular attacks. This suggests that IBS was not simply diagnosed in and around the time of the diverticulitis attack, but was identified in the months and years after. Although this, too, cannot prove a causal link between diverticulitis and subsequent IBS, it provides further evidence that diverticulitis may have preceded IBS, and not vice versa. It further argues against a misclassification at the time of the index attack because one might expect new IBS diagnoses to occur closer to the index date in the case of misclassification, not in the months and years to follow.

Third, we supported these bowel symptom analyses by evaluating a related yet very different outcome—incident depression and related mood disorders. Because chronic bowel disorders are associated with depression, especially IBS,²⁷ we hypothesized that diverticulitis cases would have a higher incidence of affective diagnoses vs matched controls; shows this finding. Coupled with finding a higher incidence of long-term chart-confirmed IBS and functional bowel diagnoses in cases vs controls, these results support the hypothesis that diverticulitis might trigger long-term physical and emotional symptoms well beyond the acute event.

The development of PDV-IBS is biologically plausible. Research has shown potentially shared pathophysiologic mechanisms between IBS and symptomatic diverticular disease. There are reports that some IBS patients show low-grade colonic inflammation in the absence of macroscopic colitis.⁵ Moreover, inflammation may alter gastrointestinal reflexes, amplify visceral sensitivity, render the bowel more susceptible to negative effects of microbiota, and alter motility in IBS.⁵ Similarly, some small studies have shown chronic microscopic inflammation in biopsy specimens taken from within and around diverticula in patients with symptomatic diverticular disease.^12,28,29 Similar to IBS, patients with diverticular disease have heightened visceral pain perception in response to luminal distension compared with controls.^8,14 Another putative mechanism of chronic diverticular disease involves shifts in intestinal microbiota leading to chronic inflammation, similar to theoretical models for IBS.²⁰ Several lines of evidence support a potential association between the intestinal microbiota and diverticular disease. Gut-directed antibiotics may reduce attacks of recurrent diverticulitis and treat gastrointestinal symptoms in patients with symptomatic diverticular disease^29,30; data also have shown modest benefits of antibiotics in IBS.³¹ Low dietary fiber intake, a putative risk factor for chronic diverticular disease and IBS with constipation, is also associated with alterations in the gut microbial composition³²; these changes might lead to bacterial overgrowth or even precipitate acute diverticulitis.¹² In a study of 90 patients with a history of acute diverticulitis, 60% met criteria for small intestinal bacterial overgrowth,¹⁵ a condition also purported to occur in many patients with IBS.²⁰ Finally, there is a strong and consistent link between acute bacterial gastroenteritis and PI–IBS,²³ a condition in which chronic bowel symptoms persist long after the infectious agent has cleared. Analogous to the postinflammatory model of PI–IBS, it is possible that acute diverticular inflammation may trigger PDV-IBS.

This study had several limitations. First, although we performed a longitudinal analysis, we cannot assert that diverticulitis caused IBS in this study. Although this study suggests directionality from diverticulitis to IBS, only a large prospective study can answer this question definitively. In the meantime, there is biological plausibility of a link, cross-sectional evidence from multiple previous studies, and now longitudinal evidence of a temporal relationship between diverticulitis and IBS. Second, we relied on administrative data to identify diverticulitis cases. These codes could have been applied inaccurately, and true cases may have been missed altogether. In fact, the diagnosis of diverticulitis in everyday clinical practice is often difficult because leukocytosis is not a requirement for diagnosis and CT scanning is not always performed. Thus, we used a pragmatic definition based on the same everyday clinical decisions made by providers on the front lines. However, when focusing just on those subjects with CT or surgically confirmed diverticulitis, the difference in new functional gastrointestinal diagnoses remained highly statistically significant. Future studies may better standardize the definition of diverticulitis in a prospective protocol. Last, our overall rate of IBS in this series was less than 1%; this is considerably lower than the 7% population prevalence quoted in IBS guidelines.³³ However, IBS is generally more prevalent in younger women, and this series consisted almost entirely of men with an average age of 62 years. We also excluded pre-existing diagnoses of IBS, used the more restrictive Rome criteria, and solely focused on new diagnoses during the study period— generally rare diagnosis to accumulate de novo after the age of 60 in men.

Our findings support the evolving paradigm of diverticular disease as a chronic illness, not merely an acute condition marked by abrupt complications. Far from a self-limited episode, acute diverticulitis may become a chronic disorder in some patients. Diverticulitis is correlated with not only chronic IBS symptoms but also long-term emotional distress beyond the event itself. Awareness of this possible risk is important because persistent, untreated gastrointestinal symptoms and comorbid depression may worsen outcomes and increase the economic burden of an already prevalent disease. Existing diverticulitis guidelines largely focus on acute management principles rather than chronic symptoms.^4,34 However, enhanced awareness of the potential long-term impact of diverticulitis, including the possibility of PDV-IBS, may allow for more timely diagnosis and treatment. Future research should identify demographic and clinical predictors of PDV-IBS and evaluate its incidence in prospective studies to better determine whether this link is causal or merely associative.

Irritable bowel syndrome and colonic diverticular disease: overlapping symptoms and overlapping therapeutic approaches

Purpose of review:

Irritable bowel syndrome (IBS) is a common symptomatic disorder in the Western world and colonic diverticula are also prevalent; however, relationships between IBS-type symptoms and diverticula have been a source of much debate. Our goal was to reassess these relationships in the light of new data.

Recent findings:

On removing from consideration clinical scenarios which are directly related to diverticula (i.e., diverticulitis, diverticular hemorrhage, and complications of diverticulitis, such as stricture and fistula), relationships between IBS and diverticula can be seen to revolve around a number of questions. First, are IBS and symptomatic uncomplicated diverticular disease (SUDD) the same condition? Or, in other words is SUDD no more than IBS in an individual who just happens to have diverticula? Although coincident IBS and diverticula inevitably do occur there is some evidence to indicate that SUDD may be somewhat distinctive with SUDD being characterized by more frequent and severe pain. Second, and analogous to interactions between IBS and inflammatory bowel disease or celiac disease, can an episode of acute diverticulitis lead to the de novo development of IBS? There is now epidemiological and pathophysiological evidence to support this occurrence.

Summary:

Although relationships between uncomplicated diverticular disease and IBS have been reexamined their status remains unclear. As yet, however, none of the newer concepts related to this relationship have led to new therapeutic approaches in IBS or diverticular disease.

Diverticulosis | Michigan Medicine

Topic Overview

What is diverticulosis?

Diverticulosis
is a condition that develops when pouches (diverticula) form in the wall of the colon (large intestine). These pouches are usually very small (5 to 10 millimeters) in diameter but can be larger.

In diverticulosis, the pouches in the colon wall do not cause symptoms. Diverticulosis may not be discovered unless symptoms occur, such as in painful diverticular disease or in diverticulitis. As many as 80 out of 100 people who have diverticulosis never get diverticulitis.^{footnote 1} In many cases, diverticulosis is discovered only when tests are done to find the cause of a different medical problem or during a screening exam.

What causes diverticulosis?

The reason pouches (diverticula) form in the colon wall is not completely understood. Doctors think diverticula form when high pressure inside the colon pushes against weak spots in the colon wall.

Normally, a diet with adequate fiber (also called roughage) produces stool that is bulky and can move easily through the colon. If a diet is low in fiber, the colon must exert more pressure than usual to move small, hard stool. A low-fiber diet also can increase the time stool remains in the bowel, adding to the high pressure.

Pouches may form when the high pressure pushes against weak spots in the colon where blood vessels pass through the muscle layer of the bowel wall to supply blood to the inner wall.

What are the symptoms?

Most people don’t have symptoms. You may have had diverticulosis for years by the time symptoms occur (if they do). Over time, some people get an infection in the pouches (diverticulitis). For more information, see the topic Diverticulitis.

Your doctor may use the term painful diverticular disease. It’s likely that painful diverticular disease is caused by irritable bowel syndrome (IBS). Symptoms include diarrhea and cramping abdominal (belly) pain, with no fever or other sign of an infection. For information on the symptoms of IBS, see the topic Irritable Bowel Syndrome (IBS).

How is diverticulosis diagnosed?

In many cases, diverticulosis is discovered only when tests, such as a barium enema X-ray or a colonoscopy, are done to find the cause of a different medical problem or during a screening exam.

How is it treated?

The best way to treat diverticulosis is to avoid constipation. Here are some ideas:

• Include fruits, vegetables, beans, and whole grains in your diet each day. These foods are high in fiber.
• Drink plenty of fluids, enough so that your urine is light yellow or clear like water.
• Get some exercise every day. Try to do moderate activity at least 2½ hours a week. Or try to do vigorous activity at least 1¼ hours a week. It’s fine to be active in blocks of 10 minutes or more throughout your day and week.
• Take a fiber supplement, such as Citrucel or Metamucil, every day if needed. Read and follow all instructions on the label.
• Schedule time each day for a bowel movement. Having a daily routine may help. Take your time and do not strain when you are having a bowel movement.

This treatment may help reduce the formation of new pouches (diverticula) and lower the risk for diverticulitis.

Can diverticulosis be prevented?

Eating a high-fiber diet, getting plenty of fluids, and exercising regularly may help prevent diverticulosis.

Misdiagnosis of Diverticulitis After a Prior Diagnosis of Irritable Bowel Syndrome (IBS)

Abstract

Introduction: Irritable bowel syndrome (IBS) and diverticulitis share clinical features. Misdiagnosed diverticulitis can cause unnecessary antibiotic therapy. Among IBS and non-IBS patients, we compared outpatient, clinically diagnosed (no computed tomography) diverticulitis rates. Among primary-care, diverticulitis-diagnosed IBS patients, we assessed imaged diverticulosis and probable misdiagnosed diverticulitis.

Methods: Among 3836-patient IBS and 67,827-patient non-IBS cohorts identified from 2000 to 2002, we retrospectively compared the frequency of outpatient, clinically diagnosed, antibiotic-treated diverticulitis from 2003 to endpoints of December 31, 2017, disenrollment, or death. In IBS patients, we reviewed records of initial, primary care-managed episodes for misdiagnosis.

Results: In 3836 clinically diagnosed IBS and 63,991 non-IBS cohorts, followup (median [interquartile range]) was 12.4 (3.9 to 15.0) years versus 10.2 (3.0 to 15.0) years, respectively (P < .001). The incidence rate/1000 patient-years (95% CI) of diagnosed diverticulitis was 14.0 (12.1 to 16.3) and 4.2 (4.0 to 4.5), respectively, (crude incidence rate ratio, 3.3 [2.8–3.9]; P < .001). Of examined features, the diagnosis of IBS was most strongly associated with clinically diagnosed diverticulitis (adjusted incidence rate ratio [95% CI]; 2.64 [2.21–3.15], P < .001). Of initial diverticulitis diagnoses in 189 IBS patients, objective evidence-based diagnosis revision or exclusion occurred in 12 (6.3%), including 6 hospitalized; 29 (15.3%) had colon imaging before and/or afterward without diverticulosis reported; 143 (75.1%) had image-documented diverticulosis; and 6 (3.2%) had no imaging.

Conclusions: Outpatient, clinically diagnosed, antibiotic-treated diverticulitis was increased 3-fold in IBS patients. Primary care clinical misdiagnosis of initial episodes occurred in 1 of 5 patients, but additional misdiagnosis due to misattribution of IBS pain to diverticulitis is suggested.

Introduction

Irritable bowel syndrome (IBS), a common functional disorder, is clinically diagnosed by typical symptoms and exclusion of organic disease, usually by limited testing. It is characterized by recurrent abdominal pain and disordered bowel habits.¹ Colonic diverticulosis is also common, but only a minority of patients with it develop acute diverticulitis.^2,3 Abdominal pain is the most common gastrointestinal symptom prompting outpatient visits,⁴ and diverticulitis is often diagnosed in outpatients.^5,6 Abdominal pain varies from mild to severe in both IBS⁷ and diverticulitis, and abdominal tenderness is found with both disorders.^1,7⇓–9 Furthermore, many patients with diverticulitis report constipation or diarrhea.^8,10,11 These shared clinical features, the frequent absence of fever and leukocytosis,⁸ and common uncertainty about whether a patient has diverticulosis promote confusion of IBS with diverticulitis.^11,12 Outpatients diagnosed with diverticulitis are often treated with antibiotics, so misdiagnosis can result in unnecessary antibiotic therapy.

In a retrospective long-term cohort study, we aimed to 1) compare health examinees with and without IBS regarding the frequency of outpatient clinically diagnosed (no computed tomography), antibiotic-treated diverticulitis and assess associated patient features; and 2) assess imaging reports of diverticulosis, a prerequisite for diverticulitis, and documented misdiagnosis among IBS patients who had an initial primary care diagnosis of diverticulitis.

Methods

Study Setting, Patients, and Data Sources

We enrolled consecutive patients ≥ 18 years of age who had undergone a health screening evaluation during 3 years in the San Diego service area of Kaiser Permanente–Southern California (KPSC), an integrated, prepaid health care system whose members reflect the diversity of Southern California by census.¹³ All KPSC members have a primary care physician. On October 7, 2007 article records were replaced by electronic medical records. Before that date complete records, including radiologic imaging reports, may not have always been available at outpatient visits; beginning then comprehensive electronic records were uniformly available. Electronic databases included the Charlson Morbidity Index (comprised of potentially life-limiting diseases), comprehensive pharmacy dispensing data and diagnosis coding of all patient encounters using the International Classification of Diseases, Ninth Revision (ICD-9) before October 2015 and the International Classification of Diseases, Tenth Revision (ICD-10) thereafter. Coding staff review codes for all emergency department and inpatient encounters and samples of outpatient encounters.

Identification of IBS and Non-IBS Cohorts

Subjects had previously submitted a self-completed, pre-examination questionnaire eliciting demographic, symptom, and medical/surgical history data, between 2000 and 2002 as part of a separate Institutional Review Board–approved project.¹⁴ As previously described, we validated a question on whether a physician had diagnosed IBS by comparing the responses with documented physician diagnosis in the medical records. Agreement occurred in 83.6% of 201 patients (ĸ = 0.82).¹⁴ Therefore, examinees were placed in the IBS or non-IBS cohorts according to the question response. We excluded patients initially without IBS who were diagnosed with IBS during followup as identified by ICD-9 code 564.1 and ICD-10 code K58.

Identification of Diverticulitis

We identified diverticulitis from an outpatient ICD-9 code (562.11 or 562.13) or ICD-10 code (K57.20, K57.30, K57.92, or K57.93) and pharmacy dispensing of an antibiotic ≤ 7 days after diagnosis. The outpatient settings comprised nonhospital offices, including after-hours urgent care clinics. Emergency department visits were not included. Most of the practitioners were primary care physicians, but nurse practitioners and physician assistants working under their supervision likely diagnosed some cases. As previously published, we developed this case finding method in a pilot sample by assessing multiple computerized algorithms based on electronic data, including diagnosis codes, dispensing of antibiotics and pain medication and/or pain diagnoses, and excluding patients with infections and/or conditions that could mimic diverticulitis. Testing the method in 1502 randomly selected KPSC members revealed a sensitivity of 84.6% and positive predictive value of 98.1% for physician-diagnosed diverticulitis in outpatients.¹⁵ As we assessed only clinically diagnosed diverticulitis, we excluded patients who had undergone computed tomography (CT) of the abdomen and/or pelvis with or without oral contrast ≤ 14 days before diagnosis, identified by Current Procedural Terminology codes 74176 to 74178, 74150, 74160, and 74170. We assessed the frequency of outpatient, clinically diagnosed, antibiotic-treated diverticulitis diagnosis from January 1, 2003 to December 31, 2017.

Evaluation of the IBS Cohort for Misdiagnosis and Diverticulosis Documentation

Two gastroenterologists independently reviewed the medical records of patients in the IBS cohort who had an initial episode of outpatient clinically diagnosed, antibiotic-treated diverticulitis. They recorded data from the outpatient visits when the diagnoses were made, including clinical features and leukocyte counts. Fever was defined as temperature > 37.5°C and leukocytosis as >11,500 leukocytes/mm³. They searched outpatient visit records, hospitalization summaries, and laboratory and pathology reports following the visit for evidence of a revised diagnosis with changed therapy or exclusion of diverticulitis, the latter requiring CT ≤ 3 days after diagnosis that revealed no colonic wall thickening, inflammation of peri-colic fat, or other findings of diverticulitis. They recorded all barium enema, flexible sigmoidoscopy, colonoscopy, and abdominopelvic CT procedures performed before and after the diagnosis and considered the patient as having diverticulosis if a single procedure reported diverticulosis of any severity. Patients with multiple imaging tests were classified as having no diverticulosis only if no procedure reported it, either before or after the diagnosis. The reviewers resolved any discrepancies by joint record review.

Statistical Analysis

We summarized categorical data as percentages and continuous data as mean ± standard deviation (SD) or median (interquartile range) as appropriate. We compared categorical data with the c² test and continuous data with the Student’s t-test. Incidence rates per 1000 patient-years were calculated and corresponding 95% CIs were estimated using robust Poisson regression. Controlling for age, sex, race/ethnicity, and all other medical and surgical history variables from the patient questionnaires (Table 1), multivariable Poisson regression was fitted to derive the adjusted incidence rate ratio of diverticulitis in the IBS cohort versus the non-IBS cohort. All tests were 2 tailed, and the level of significance was < .05. We used SAS statistical software (version 9.4; SAS Institute, Cary NC).

Table 1.

Baseline Demographic, Medical, and Surgical Features in 67,827 Examinees with and without IBS (2000–2002)

Results

Patient Features

Demographic and history features differed between the 3836 subjects in the IBS cohort and the 63,991 subjects in the non-IBS cohort (Table 1), as previously described in the larger cohorts from which they were derived.¹⁴ Length of followup was 12.4 (3.9 to 15.0) years versus 10.2 (3.0 to 15.0) years in IBS and non-IBS cohorts, respectively (P < .001).

Diverticulitis Diagnosis Frequency and Associations in IBS and non-IBS Cohorts

Of 89,008 examinees, we excluded 21,181 as detailed in Figure 1, yielding 67,827 examinees, 3836 (5.7%) IBS and 63,991 (94.3%) non-IBS examinees. Additional exclusions by electronic database criteria yielded 290 IBS individuals with 523 episodes and 1669 non-IBS individuals with 2455 episodes.

Figure 1.

Flowchart summarizing derivation of the cohorts with and without irritable bowel syndrome by electronic database criteria. *Number of unique patients/number of episodes. Abbreviations: CT, computed tomography; IBS, irritable bowel syndrome.

At least 1 episode of clinically diagnosed, antibiotic-treated diverticulitis occurred in 290 of 3836 (7.6%) and 1669 of 63,991 (2.6%) outpatients with and without IBS, respectively (P < .001). The incidence rate (95% CI) per 1000 patient-years of outpatient clinical diagnosis and antibiotic treatment was 14.0 (12.1 to 16.3) versus 4.2 (4.0 to 4.5) in IBS and non-IBS cohorts, yielding a crude incidence rate ratio of 3.3 (2.8 to 3.9) (P < .001).

Multivariate Poisson regression revealed that of the patient features, IBS was most strongly associated with outpatient diagnosis (Table 2). Age was only negligibly associated, and a race/ethnicity association varied from negative associations in Asians/Pacific Islanders and blacks to a positive association in Hispanics compared with whites. Frequent headaches, current smoking, hypertension, cholecystectomy, and back surgery were positively associated, and vegetarianism and diabetes were negatively associated. The Charlson Comorbidity Index was not associated with the diagnosis.

Table 2.

Patient Features Associated with Clinically Diagnosed Diverticulitis in 1959 Examinees, 290 with IBS and 1669 Without IBS, During Followup (2003 to 2017)

Initial Outpatient, Clinically Diagnosed, Antibiotic-Treated Diverticulitis in the IBS Cohort

To identify initial episodes of diverticulitis during followup in the IBS cohort, we excluded patients electronically from the total 3836-patient IBS cohort for a diverticulitis history, lack of outpatient diagnosis, use of CT and lack of antibiotic treatment, yielding 204 patients (Figure 2). Record review led to exclusion of 15 additional patients, yielding a final cohort of 189 IBS patients with an initial episode (Figure 3). The age (mean SD) at diagnosis was 65 ± 12.7 years, and 142 (75.1%) were female. Clinical and laboratory records were available on all patients. Temperature was recorded on 118 (62.2%) patients. Abdominal pain, tenderness, and fever occurred in 181 of 189 (95.8%), 176 of 189 (93.2%) and 3 of 118 (2.5%) patients, respectively. Of 76 (40.2%) patients who had a leukocyte count performed, 26 (34.2%) had leukocytosis.

Figure 2.

Flowchart summarizing derivation by electronic database criteria of the subcohort of irritable bowel syndrome patients who had an initial episode of outpatient clinically diagnosed, antibiotic-treated diverticulitis during followup (2003 to 2017). Abbreviations: CT, computed tomography; IBS, irritable bowel syndrome.

Figure 3.

Flowchart summarizing further derivation by record review of the subcohort of irritable bowel syndrome (IBS) patients who had an initial episode of outpatient clinically diagnosed, antibiotic-treated diverticulitis during follow-up (2003 to 2017). Patients are classified according to revision or exclusion of the diagnosis, colon imaging and diverticulosis documentation.

Misdiagnosis and Diverticulosis Documentation in the IBS Cohort

Figure 3 also summarizes patients whose diverticulitis diagnosis was revised or excluded and the results of colon imaging studies. Within 2 weeks after antibiotics were dispensed for diverticulitis, 12 (6.3%) patients were found to have objective evidence of another etiology for their presenting features (11) or lack of diverticulitis on CT (1). As detailed in Table 3, diseases in the 11 patients were Clostridium difficile colitis (2), urinary tract infection (2), Crohn’s disease (2), cholecystitis (1), small bowel obstruction (1), sigmoid volvulus (1), and ovarian cyst (1), and cholecystitis and pancreatitis (1). Six of the patients were hospitalized, and all 12 survived. CT was performed in 3 additional patients 1 to 7 days after diagnosis, which confirmed diverticulitis in all.

Table 3.

Twelve Patients with Irritable Bowel Syndrome Whose Diagnosis of Diverticulitis Was Subsequently Revised or Excluded (2003 to 2017)

Twenty-nine (15.3%) patients had no diagnosis revision, but they had colon imaging that did not reveal diverticulosis before and/or after diagnosis. As detailed in Appendix, the age of these patients ranged from 25 to 84 years, 26 (89.7%) were female, and at least 1 procedure revealing no diverticulosis occurred before, after or both before and after diagnosis in 5, 15, and 9 patients, respectively. Nineteen (65.5%) patients had > 1 negative procedure, including 11 who underwent ≥ 3 procedures.

Combined with the revised diagnoses or CT exclusion of diverticulitis in 12 patients, a lack of diverticulosis on imaging supported misdiagnosis in 41 of 189 (21.7%) patients. One hundred forty-two (75.1%) patients (age 66.3 ± 11.4 years; 58 [40.8%] < 65 years; 102 [71.8%] female) had a diagnosis that was not revised nor excluded by CT and had imaging before and/or after the episode that revealed diverticulosis. Six (3.2%) had no colon imaging.

Discussion

In this retrospective, long-term, cohort study of health examinees, patients with an IBS diagnosis had a 3-fold increase in the frequency of outpatient, clinically diagnosed and antibiotic-treated diverticulitis compared with those without IBS. Of the features assessed in association with diverticulitis, the strongest association was found with diagnosis of IBS. In patients with IBS and an initial episode of diverticulitis managed in primary care, diagnosis revision and changed therapy occurred in 6.3% of patients. An additional 15.3% of patients had colon imaging studies before and/or after the diagnosis that reported no diverticulosis. These findings support misdiagnosis in 1 of 5 patients.

Published evidence is lacking to support such a strong association between IBS and diverticulitis, as we found. An association was reported between IBS, especially diarrhea-predominant IBS, and diverticulosis only in patients aged ≥ 65 years, but not with diverticulitis.¹⁶ Another survey found an association between IBS and diverticulosis only in patients > 60 years but did not assess diverticulitis.¹⁷ We did not determine bowel habit predominance; 40.8% who had diverticulosis diagnosed and lacked evidence of misdiagnosis were < 65 years when initially treated for diverticulitis. Therefore, it seems unlikely that increased diverticulosis alone explained the 3-fold increased rate of physician-diagnosed diverticulitis in the IBS cohort.

Diagnosis of diverticulitis in our IBS cohort was primarily based on abdominal pain and tenderness, as fever and leukocytosis were infrequent. Surgeons have also reported on the scarcity of objective evidence of diverticulitis diagnosed in most clinic patients and suggested that many outpatients have mild disease or no diverticulitis at all.^6,18 However, we are unaware of other investigations that compared the frequencies of the outpatient clinical diagnosis of diverticulitis in patients with and without IBS or attempted to document misdiagnosis in IBS patients.

Some of the patients had life-threatening disorders. Other patients lacked diagnosis revision or CT exclusion of diverticulitis and had colon imaging, two thirds with multiple procedures, without a report of diverticulosis.

These 2 types of misdiagnosis may not fully explain the greatly increased diverticulitis frequency in IBS patients. Just as increased abdominal and pelvic surgery in the IBS cohort was attributed to symptom misattribution,¹⁴ abdominal pain and tenderness could have been incorrectly attributed to diverticulitis. Such misattribution was proven in only 1 case, but few patients had CT before symptoms resolved to allow this assessment, which is typical in outpatient settings. There is evidence of a deficiency in physician awareness of features of IBS patients, including their health care–seeking behavior. Surveys of American¹⁹ and European²⁰ primary care physicians revealed only a minority knew important aspects of IBS or used the Rome diagnostic criteria. About three quarters of American primary care physicians regarded IBS as a diagnosis of exclusion and relied less on symptoms and ordered more tests than specialists.²¹ To our knowledge, primary care physicians’ awareness of abdominal tenderness in IBS has not been systematically studied, although a landmark publication almost 60 years ago⁷ detailed tenderness in over 60% of patients. Furthermore, patient reactions to abdominal palpation can help distinguish functional from structural disorders.²²

Limitations include our inability to identify which IBS patients with diverticulosis and no other etiology evident for their acute symptoms, had diverticulitis versus a flare of IBS or another disorder. We cannot exclude the possibility that IBS was incorrectly diagnosed and that in follow-up diverticulitis was mimicked by another disease or coexisted with it, such as the Crohn’s disease in 2 patients; however, most of the misdiagnoses were acute diseases. Symptoms of patients attributed to IBS are infrequently changed to another etiology over the long term.²³ The high prevalence of diverticulosis and usual requirement of CT to confirm diverticulitis challenge any study of clinically diagnosed diverticulitis, retrospective or prospective. The predominant bowel pattern of the IBS patients was not determined, but all subtypes are characterized by abdominal pain.¹ We did not investigate misdiagnosis in subjects without IBS.

Strengths of the study include large cohorts with validated methods of identifying physician-diagnosed IBS¹⁴ and diverticulitis¹⁵ that were assessed for a median of at least 10 years. We utilized comprehensive databases in a prepaid health care system, double-physician record review and objective evidence for revised diagnoses and exclusion of diverticulitis. We had computerized laboratory, radiology, pathology, physician diagnosis, and other data on all patients, enabling us to detect revised diagnoses by objective criteria. Agreement rates between colon imaging procedures range from 60% to 82%, but we accepted the presence or absence of diverticulosis revealed by any colon imaging procedure.¹⁸ We required absence of diverticulosis of any severity from all colon imaging studies in IBS patients with multiple procedures before and/or after initial diverticulitis diagnosis to classify them as not having diverticulosis. With this method, we considered some patients as having diverticulosis if an imaging test revealed diverticulosis several years after their initial diverticulitis diagnosis, even if multiple prediagnosis procedures reported no diverticulosis. Patients with negative imaging before initial diagnosis and no subsequent imaging could have developed diverticulosis before diagnosis. However, three quarters of patients classified as without diverticulosis had none reported on imaging after or both before and after diagnosis. Therefore, our strict definition of absent diverticulosis at any time likely classified some patients as having diverticulosis who did not have the disorder when diverticulitis was diagnosed. To minimize potential diagnostic bias related to a prior outpatient diagnosis, we assessed only the initial episodes in the IBS cohort. Our findings seem generalizable because similar proportions (about 70%) of diagnosed patients are managed as outpatients in our health care system and in a university system,^5,6 and most outpatients with abdominal pain initially present to primary physicians.

Our findings are relevant to research and practice. Studies in which case finding includes outpatient clinical diagnoses could overestimate cases. In patients with chronic recurrent pain, physicians should be circumspect when a patient reports pain that was previously attributed to diverticulitis from clinical features alone.

Accepted practice calls for physicians to consider how IBS patients’ abdominal pain and associated symptoms compare with their usual recurrent symptoms. Consideration of the psychosocial background and prior health care-seeking behavior, including amplified reporting of multiple symptoms and consultation^24,25 is particularly important in patients with severe pain.^26,27 However, based on clinical and laboratory findings alone⁸ both primary physicians and gastroenterologists will be uncertain as to whether some patients have diverticulitis.

How should physicians manage IBS patients with suspected diverticulitis? The American Gastroenterological Association suggested selective rather than the traditional routine use of antibiotics in uncomplicated diverticulitis,²⁸ and additional data supported the safety of management without antibiotics.²⁹ Although mistaken diagnosis of diverticulitis in IBS patients likely represents a minority of all outpatients treated for diverticulitis, avoiding antibiotic use in suspected diverticulitis would reduce the increased rates of antibiotic use and Clostridium difficile infection that we previously documented in the IBS cohort.³⁰ Routine antibiotic treatment of diverticulitis may be more likely in the United States than in England where antibiotic use and Clostridium difficile infection have decreased. ³¹ It is prudent to manage selected outpatients with close observation and without antibiotics after careful clinical evaluation and relevant laboratory testing. The mean duration of episodically increased abdominal pain in IBS is 3 days.³² Failure to improve could lead to consideration of other tests and/or antibiotic treatment.

In conclusion, diverticulitis was diagnosed much more often in outpatients with IBS than those without IBS. This finding was partly attributable to mistaken attribution of presenting features of other diseases to diverticulitis. In other patients, absence of diverticulosis indicated misdiagnosis. Although the findings revealed misdiagnosis in about 1 of 5 patients, we speculate that additional patients had misattribution of abdominal pain and tenderness to diverticulitis. In view of the common uncertainty of outpatient diverticulitis diagnosis and safety of treating many documented cases without antibiotics, it is advisable to consider withholding these drugs in suspected cases. Further research could aim to identify clinical features that improve the accuracy of clinical diagnosis in primary care.

Are They Related to IBS?

Conditions affecting the bowel can often be tricky to diagnose.

Symptoms such as diarrhoea, constipation and bloating can have a number of causes.

Where these problems develop very quickly and pass after a short period, a viral or bacterial infection may be responsible.

However in cases where these symptoms return intermittently or persist, then further investigation may be required to determine what is causing them.

In some instances, there might not be just one cause, and the conditions contributing towards symptoms may overlap.

Different chronic conditions affecting the digestive tract can often have much in common; and in some instances, one condition might be related to or increase the risk of another.

Irritable bowel syndrome, as we’ve written before, is fairly common. When we spoke to the IBS Network, they told us that somewhere between 10 and 20 percent of all persons residing in Western countries would at some point display symptoms that adhere to the ‘diagnostic criteria’ for this condition.

Diverticular disease, in terms of outward symptoms at least, can appear similar to IBS. Bloating, constipation and diarrhoea are characteristics these two conditions share.

But are these two particular conditions related?

What is IBS?

Irritable bowel syndrome is characterised by food moving either too quickly or too slowly through the gut.

Rhythmic muscular contractions in the large intestine manage the speed at which food passes through. In those with IBS, it is thought that this rhythm is somehow disrupted.

This can result in a range of symptoms, including:

Further symptoms that may occur as a result of IBS include:

Of course, not everyone will experience all of the above; the condition varies from person to person.

It’s not entirely understood what causes IBS, although higher gut sensitivity is widely thought to be the main instigating factor; certain foods, infections, inflammation and stress have all been cited as triggers.

Unsurprisingly, IBS can often be mistaken for other conditions. There is no definitive test to determine whether or not someone has IBS, so diagnosis typically consists of eliminating other conditions that can cause similar symptoms, such as infections, inflammatory bowel disease or food intolerances.

Treatment typically consists of making dietary changes to help alleviate symptoms, and to reduce the frequency and severity of flare-ups. However, which strategy a person adopts depends on their own individual case. For instance, reducing insoluble fibre can help with diarrhoea; whereas increasing soluble fibre and help with constipation. Practicing a low FODMAP diet can help to counter bloating.

Occasionally, certain medications can help to treat IBS. Antispasmodics work by relaxing the muscles in the bowel; whereas laxatives and antimotility drugs might be used to alleviate constipation or diarrhoea respectively.

What is diverticulosis?

Diverticulosis is characterised by the presence of diverticula. These are small pockets which form over time in the lining of the large bowel (typically in the lower descending section, known as the sigmoid colon). Diverticula are not uncommon and tend to develop with age. The NHS estimates that one in 20 will have them by the age of 40, and half of people will have them by the age of 80.

They develop as a result of the lining of the large bowel having to exert excess pressure to pass through stools. Diverticula form when weak spots appear in the muscle lining, and the mucosal layer on the inside of the bowel pushes through these.

Once more, no ultimately definitive answer has put been put forth as to why some people develop diverticula and others don’t, but there is thought to be a strong link between the formation of diverticula and a lack of dietary fibre.

In many instances, the presence of diverticula alone will not cause any significant problems. Only around one in four of those who have not had diarrhoea or abdominal discomfort will go on to develop symptoms.

Unsurprisingly then, it is entirely possible for someone to have diverticula for many years and not know.

What is diverticular disease?

Where symptoms occur as a result of diverticula, this is known as diverticular disease. These symptoms might be:

• Stop/start pain, usually in the lower to left abdomen

• This pain may be worse during eating, and be relieved by passing stool

• Feeling bloated

• Constipation or diarrhoea, passing small pellet-like stools

Rarely, someone with diverticular disease may also pass dark or purple blood with their movements. This is a complication which will require hospital treatment. (Anyone who notices blood in their stools, purple or otherwise, should speak to their doctor as soon as possible.)

Diagnosis is made utilising a series of tests. Blood testing is commonly a first option. This will help doctors to eliminate the possibility of bowel cancer or IBD.

When these conditions have been ruled out, the presence of diverticula is often confirmed through an examination of the bowel (colonoscopy). This is where a camera on a tube is inserted into the rectum.

How diverticular disease is treated will be determined by how serious it is. In many cases, treatment can be administered at home. Paracetamol can help to reduce associated pain, and eating a high fibre diet can help to make bowel movements more consistent.

What is diverticulitis?

When one or several of the diverticula becomes infected, this can result in diverticulitis. This might occur due to a fragment of stool getting stuck in one of the pockets. The bacteria in the trapped fragment then transfers into the tissue and develops into an infection.

In diverticulitis, someone may have the symptoms of diverticular disease but also experience:

According to the International Foundation for Functional Gastrointestinal Disorders (IFFGD), between one in five and one in seven people with diverticula (roughly 15-20 percent) will go on to develop diverticulitis.

Someone’s risk of developing diverticulitis is thought to be higher if they:

Persons with an immediate family member who also has diverticular disease may also have a higher risk.

A diagnosis of diverticulitis might be made based on symptoms if a patient is known to have diverticular disease. But if they don’t, further testing may be required.

Treatment depends on how severe diverticulitis is. In milder instances, someone may be advised to take oral antibiotics to kill the infection, follow a liquid-only diet for a few days in order to let the bowel rest, and recover at home.

More serious cases (such as if the infection doesn’t improve after treatment at home, if complications are present or likely, or if oral antibiotics are not suitable) will require hospital admission. Antibiotics in this case may be administered via injections.

Where someone carries a very high risk of developing complications from diverticulitis, surgery to remove the section of colon affected by be necessary.

Are IBS and diverticular disease linked?

Diverticular disease can often be mistaken for IBS. Both conditions can produce similar symptoms such as bloating, pain, and changes in bowel frequency.

IBS is a long-term condition which goes through periods of flare-up and remission. But according to the IFFGD, it does not increase the risk of other gastrointestinal diseases (such as diverticulitis) developing.

However, recent research suggests that those who have had diverticulitis may be more likely to develop IBS symptoms.

A UCLA study in 2013 compared 1,102 post-infection patients with 1,102 matched controls over an average of 6.3 years; and found that those who had had diverticulitis were almost five times more likely to later be diagnosed with IBS than those in the control group.

The name the UCLA researchers proposed for this phenomenon was post-diverticulitis IBS (PDV-IBS).

Higher rates of anxiety were also observed in the post-infection group, which the lead researcher commented could trigger IBS symptom-inducing processes in the ‘brain-gut axis’.

Based on these findings, they noted that despite being an acute illness, diverticulitis may have the capacity to cause chronic ramifications.

It should be noted however that research into the association between these two conditions is still at a relatively early stage.

When to see a doctor

It’s important to report any significant changes in bowel habits to your GP, so that you can have the cause of them identified. Your doctor will be able to assist you in getting the treatment you need; whether it involves referral for further testing, or helping you to develop a diet plan to reduce or manage symptoms.

IBS and Diverticulitis

Diverticulitis, although not Irritable Bowel Syndrome (IBS), is closely related to IBS.

What is Diverticulitis?

Diverticulitis is the diagnosis given to people who develop inflammation as a result of diverticulosis. Diverticulosis is the presence of weak pouches in the colon called diverticula. Diverticulosis is generally diagnosed from a colonoscopy or a barium contrast x-ray.

It is estimated that by the age of 70 at least 50% of the American population has developed diverticulosis. Diverticulosis by itself does not cause symptoms, but as a result of it some people will develop diverticulitis and thus pain in the lower abdomen, often associated with diarrhea.

Diverticulitis vs IBS

The difference between diverticulitis and IBS is usually subtle, which is why these two conditions can be easy to confuse. The symptoms may be exactly the same, but the difference is seen only by your doctor, either on an abdominal CT scan or during a colonoscopy.

In either case, the pockets of diverticula are what the doctor sees on these exams. Your experience of these two conditions, however, may be the same, although sometimes people with diverticulitis also have an infection with a fever. Even doctors have trouble differentiating between these two conditions, as highlighted in this study Clinically Diagnosed Acute Diverticulitis in Outpatients: Misdiagnosis in Patients with Irritable Bowel Syndrome.

What Causes Diverticulosis?

Diverticulosis is generally thought to be caused by excessive pressure in the colon, which may be combined with a weakening of the colon due to age, inflammatory damage, or both. This pressure is likely directly associated with constipation, although many people don’t recognize themselves as having constipation. What many people have come to think of as normal bowel habits may be far from healthy or normal.

The prevailing theory is that a lack of fiber in the diet ultimately leads to the development of weak pouches in the colon. This is basically another way of saying that people don’t eat enough vegetables and don’t have as healthy of a diet as they should. How many other conditions can you think of that are caused by the same problem? Also, like many chronic conditions, the incidence is far higher in western countries than in the rest of the world, and people from other countries who switch to a western diet have a much higher incidence of diverticulosis.

How is Diverticulitis Treated?

Diverticulitis patients are encouraged to increase their intake of fiber and water. If a fever develops, then they are given antibiotics for the infection.

Unfortunately, a significant number of people with diverticulosis develop so much damage to their colon that they require surgery. Surgery is performed to remove the damaged portion of the colon, and in some cases results in the removal of the entire colon.

Although this resolves the diverticulosis, it doesn’t address the original cause of the damage. And in many cases, people continue to suffer from abdominal pain and other digestive symptoms.

The real issue remains: Why was there so much damage and inflammation in the first place?

The answer is usually far more complicated than a simple lack of fiber or water. The same issues that cause inflammation and digestive symptoms in IBS also cause problems in diverticulosis. The two primary areas of concern that need to be addressed are food allergies and imbalances in the ecosystem of the digestive tract. These are complex issues and are rarely addressed properly.

IBS and Diverticulitis FAQs

How do I tell if I have diverticulitis or IBS?

Diverticulitis must be evaluated by your gastroenterologist. Once it is established you have diverticulosis, then whenever you get lower abdominal pain it is often assumed that you are suffering from diverticulitis. This may or may not be true. It’s very difficult to know for sure, and often you are suffering from IBS, or both diverticulitis and IBS.

Can you have diverticulitis and IBS?

Yes, you can have both simultaneously. It’s a very common problem. Many people who think that they are suffering from diverticulitis are actually having a flare-up of IBS. And having one of these conditions increases the risk of developing the other.

Foods to avoid with diverticulitis and IBS?

Doctors often recommend that people with diverticulitis avoid nuts and seeds. The theory is that these types of foods will not be well digested, and then will make it to the colon and will get stuck in the diverticula. Once stuck in the diverticula they will, in theory, cause an infection which will lead to diverticulitis. It’s a very convincing idea, but there has never been any direct evidence that this is what indeed causes diverticulitis. Studies have not shown that foods are getting stuck in the diverticula.

What does an IBS diverticulitis diet include?

There is no single diet that will be successful for all IBS and diverticulitis sufferers. A diet that successfully prevents IBS or diverticulitis will vary a great deal from patient to patient. However, the good news is that there is a diet that will make a huge difference in how you feel. But you must work with an expert to find the right diet for you.

Can IBS lead to diverticulitis?

There is no medical evidence that suggests that IBS leads to diverticulitis. However, this IBS diverticular disease research study proved, people with IBS have a significantly increased risk for developing diverticulosis. This explains why people can have both IBS and diverticulitis, and why they often get them confused.

Can diverticulitis lead to IBS?

Diverticulitis can lead to IBS. Some people develop IBS after an attack of diverticulitis. This is known as post diverticulitis IBS. However, this probably does not occur as often as originally thought. There is a high frequency of IBS initially being misdiagnosed as diverticulitis according to this diverticulitis research study that focused on misdiagnosis in patients with IBS. This may give the impression that diverticulitis was first and subsequently led to the development of IBS.

What is post diverticulitis IBS?

Diverticulitis is considered an infection of the diverticula. Post diverticulitis IBS is essentially the same as post-infectious IBS. It may be diagnosed when one begins to experience IBS after an attack of diverticulitis. Fortunately, this form of IBS is also treatable.

What are the best probiotics for IBS and diverticulitis?

There are literally hundreds of different kinds of bacteria that live in your digestive tract, and therefore hundreds of different kinds of probiotics. The best probiotics for treating IBS and diverticulitis will vary based on the individual needs of the patient. This must be properly assessed before any recommendation can be made on which probiotics are best for that patient.

Ready to Treat Your Diverticulitis
Successfully treating diverticulitis remains a key component of what we do at the IBS Treatment Center and is very similar to our approach to IBS. To learn more about our approach, please give us a call 888-546-6283 at or schedule an appointment with us. We have a telemedicine option so there is no need to come to our office in person.

90,000 Intestinal diverticula and their side effects

Siegbert Rossol, gastroenterologist, specialist in internal medicine

Since 2006 he has been the chief physician of the Nordwest Medical Clinic.

More about the specialist →

Digestive problems, abdominal pain and regular stool disturbance after meals can all indicate symptoms of a diverticulum or intestinal diverticulosis.

Diverticula usually occur in the colon, in this case small protrusions in the intestinal wall, which are harmless in themselves, but can cause recurrent gastrointestinal upset.Inflammation of the diverticulum can lead to serious complications.

Diverticulosis should not be underestimated. Professor Z. Rossol, specialist of the Clinic Nordwest (Frankfurt) on intestinal diseases advises to pay serious attention to these symptoms and not to postpone the visit to the doctor, because the inflammatory process can spread to the surrounding tissues, causing purulent inflammation, or cause perforation (trauma) of the intestine.

In diverticulosis, the inside of the intestine looks porous.Actually, it’s not so scary, almost every third intestine looks like this. However, food debris trapped in such bulges leads to severe and even life-threatening inflammation.

Symptoms of mild diverticulosis, such as bloating, irregular bowel movements, are common, especially in older people, and usually do not cause much discomfort.

If diverticula are found during colonoscopy, prof.Rossol recommends the following:

– eat food with a high content of ballast substances – fruits and raw vegetables, wheat bran, crushed flax seeds.

– in order to avoid constipation, it is necessary to establish regular bowel movements with the help of a diet and systematically monitor the work of the intestines;

– refuse whole grains, because undigested grains can become stuck and remain in the diverticulum. Instead of whole grain bread, it is better to use wholemeal bread.You should also be careful with fruits containing small grains such as kiwi and grapes.

– drink enough liquid: 1.5-2 liters per day.

About the treatment of diverticulosis in the clinic Nordwest

Clinical Study Acute Diverticulitis – Clinical Trials Register

Thoracoscopic diverticulectomy of the middle third of the esophagus – surgery-first.ru

Patient 74 years old.

Main diagnosis: diverticulum of the middle third of the esophagus (bifurcation – 20% among the diverticula of the esophagus)

Concomitant diseases:

COPD of moderate severity.Chronic obstructive bronchitis. Emphysema of the lungs. Pneumosclerosis. IHD: exertional angina pectoris 2 f.k. Atherosclerotic cardiosclerosis. Ventricular premature beats. Hypertension 3 tbsp. Cerebrovascular disease. Chronic cerebral ischemia on the background of arterial hypertension, atherosclerotic lesions of BCA. Dyscirculatory encephalopathy stage 2, subcompensation. Nodular euthyroid goiter. Varicose veins of the lower extremities, CVI 2 tbsp.

Complaints: for intermittent choking when swallowing solid food, feeling of heaviness behind the breastbone after eating, rarely – pain, regurgitation of food eaten.

Medical history: for a long time worried about pain and discomfort behind the breastbone, more often after eating, which were regarded as a manifestation of angina pectoris, was examined in cardiological hospitals.

In the summer of 2016, he began to notice dysphagia, lost 6 kg. In December 2016, X-ray examination revealed a large diverticulum of the middle third of the esophagus.

CT of the chest organs: along the right wall of the middle third of the esophagus, a diverticulum with clear, even contours, measuring 43x40x71mm, is determined.The lumen of the esophagus above the diverticulum is unevenly expanded to 35 mm.

EGDS: the lumen of the esophagus is expanded to 3 cm, contains a small amount of fluid. At 30 cm from the incisors on the right wall – the upper edge of the entrance to a large and deep diverticulum, its lumen contains food debris and mucus.

Video of the operation
1. With the patient in prone position or on the left side, access to the esophagus through the right pleural cavity.
2. Fits 1 – 10 mm.trocar for endovideo camera, 1 – 12 mm trocar for endoscopic instruments and stapler, 1 – 5 mm. trocar for endoscopic instruments.
3. A thick probe is inserted into the esophagus.
4. The pleura is opened over the esophagus in the projection of the diverticulum.
5. The diverticulum is mobilized all the way to the esophagus using an electric hook and an ultrasonic dissector without opening the lumen.
6. After complete mobilization, a linear stapling-cutting apparatus is applied to the diverticulum neck, the diverticulum is cut off without opening the esophageal lumen.
7. The mechanical seam is additionally sealed with a continuous hand seam.
8. To the area of ​​the suture of the esophagus is installed 1 drain

The postoperative period was uneventful, the patient was discharged from the hospital on the 9th day after the operation. The duration of the postoperative period is due to the need to correct concomitant pathology.

Learn more about the disease

Read more about features of thoracoscopic operations .

Other thoracoscopic operations:

Treatment in the Department of Thoracoabdominal Surgery and Oncology is carried out within the framework of programs OMC , VHI, as well as on a commercial basis .
Surgical treatment of esophageal diverticulum can also be performed as part of an upper urinary tract. Read more about free high-tech medical care .