Increased Incidence and Recurrence Rates of Acute Diverticulitis in Patients with Irritable Bowel Syndrome

Aims: Acute diverticulitis (AD) is commonly diagnosed in the outpatient and emergency departments, and is associated with severe complications such as perforation and fistula. Symptoms in irritable bowel syndrome (IBS) such as abdominal pain, constipation and diarrhea are also common with AD. This study aimed to evaluate the strength of a possible association between IBS and AD.

Methods: This retrospective study analyzed records from Taiwan's National Health Insurance Research Database (NHIRD) and involved a total of 25,810 patients, including 12,905 IBS patients diagnosed between 2000 and 2012. The IBS and non-IBS cohorts were matched by propensity score for age, gender, comorbidities and medication, then compared for confounding variables by the Chi-square test or Student's t-test. The association between AD and IBS was determined using Cox proportional hazards models. Kaplan-Meier curves assessed the cumulative incidence of AD in IBS patients.

Results: The overall incidence of AD was 3.95-fold higher in the IBS cohort compared with the non-IBS cohort (63.34 vs 16.02 per 100,000 person-years, respectively) and IBS was an independent risk factor for subsequent AD diagnosis in a multivariate Cox proportional hazards regression model adjusted hazards ratio (aHR = 3.84, 95% CI = 2.29-6.44, p<0.001) and in Kaplan-Meier analysis (log-rank test, p<0.001). IBS was also associated with a high recurrence rate of AD (aHR = 8.30, 95% CI = 1.07-64.30, p=0.04).

Conclusions: The epidemiological evidence in this study demonstrates that patients with IBS are associated with a higher incidence of AD and also its recurrence.

Keywords: National Health Insurance Research Database; acute diverticulitis; irritable bowel syndrome; retrospective cohort study.