Prevalence, Risk Factors, and Outcomes of Irritable Bowel Syndrome After Infectious Enteritis: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS Foodborne illness affects 15% of the US population each year, and is a risk factor for irritable bowel syndrome (IBS). We evaluated risk of, risk factors for, and outcomes of IBS after infectious enteritis. METHODS We performed a systematic review of electronic databases from 1994 through August 31, 2015 to identify cohort studies of the prevalence of IBS 3 months or more after infectious enteritis. We used random-effects meta-analysis to calculate the summary point prevalence of IBS after infectious enteritis, as well as relative risk (compared with individuals without infectious enteritis) and host- and enteritis-related risk factors. RESULTS We identified 45 studies, comprising 21,421 individuals with enteritis, followed for 3 months to 10 years for development of IBS. The pooled prevalence of IBS at 12 months after infectious enteritis was 10.1% (95% confidence interval [CI], 7.2-14.1) and at more than 12 months after infectious enteritis was 14.5% (95% CI, 7.7-25.5). Risk of IBS was 4.2-fold higher in patients who had infectious enteritis in the past 12 months than in those who had not (95% CI, 3.1-5.7); risk of IBS was 2.3-fold higher in individuals who had infectious enteritis more than 12 months ago than in individuals who had not (95% CI, 1.8-3.0). Of patients with enteritis caused by protozoa or parasites, 41.9% developed IBS, and of patients with enteritis caused by bacterial infection, 13.8% developed IBS. Risk of IBS was significantly increased in women (odds ratio [OR], 2.2; 95% CI, 1.6-3.1) and individuals with antibiotic exposure (OR, 1.7; 95% CI, 1.2-2.4), anxiety (OR, 2; 95% CI, 1.3-2.9), depression (OR, 1.5; 95% CI, 1.2-1.9), somatization (OR, 4.1; 95% CI, 2.7-6.0), neuroticism (OR, 3.3; 95% CI, 1.6-6.5), and clinical indicators of enteritis severity. There was a considerable level of heterogeneity among studies. CONCLUSIONS In a systematic review and meta-analysis, we found >10% of patients with infectious enteritis develop IBS later; risk of IBS was 4-fold higher than in individuals who did not have infectious enteritis, although there was heterogeneity among studies analyzed. Women-particularly those with severe enteritis-are at increased risk for developing IBS, as are individuals with psychological distress and users of antibiotics during the enteritis.