Irritable Bowel Syndrome Rates Following Organic Disease of Upper and Lower Gastrointestinal Tract

Abstract

Purpose: To determine the subsequent rates of IBS among patients diagnosed with 7 diff erent organic diseases of the GI tract. Methods: Medical claims data from Ingenix Lab/Rx DatabaseTM were used to identify all subjects with the following initial diagnoses and person years of follow up: esophagitis (ICD9: 530.1x, n=367,278), gastritis & duodenitis (ICD9: 535.x, n=327,914), gastroenteritis and colitis (ICD9: 558.x, n=299,269), diverticulitis (ICD9: 562.01, 562.03, 562.11, 562.13, n=98,784), Clostridium difficile (ICD9: 008.45, n=15,724), ulcerative colitis (ICD9: 556.x, n=38,699), and Crohn's disease (ICD9: 555.x, n=29,904) during the period January 1, 2001 - December 31, 2008. To confirm the diagnosis, a second diagnosis with the same ICD9 code was required for inclusion, at any time during continuous follow up. In addition, a 12-month washout period prior to initial diagnosis was required (no history of IBS or specific GI disease). Control groups were selected for each index disease matched for age, gender and length of enrollment. All patients were then followed by diagnosis to determine subsequent rates of IBS per 1,000 person-years relative to controls, defined as the IBS rate ratio. Results: IBS rates in the control populations ranged from 5.3 to 8.4 per 1,000 person years. Rates of IBS were significantly higher in all diseases studied relative to matched control groups (p<0.01), as indicated by IBS rate ratios (see Figure). IBS rate ratios ranged from 4.1 (esophagitis) to 9 (Crohn's disease) vs. their controls. Conclusion: This study shows an increased risk of an IBS-like disorder resulting in coding as IBS associated with a number of inflammatory diseases of the gut. It is unknown to what extent anatomic location, severity or chronicity of disease contributes to relative IBS-like disorder rates. The natural history of these post-inflammatory syndromes is also deserving of further study, as well as potential interventions that might mitigate these sequelae. (Figure presented) .