Background: Case series suggest a possible association between bariatric surgery and incident inflammatory bowel disease (IBD). The aim of this study was to evaluate the association between bariatric surgery and new onset IBD in a U.S. health claims database.
Methods: We conducted a matched case-control study using medical and pharmacy claims from 2008 through 2012 in a national database from Source Healthcare Analytics LLC. Patients age 18 or older in the database since 2008 were included. New onset IBD was defined as having at least 3 ICD-9 codes for Crohn's disease (CD, 555.x) or ulcerative colitis (UC, 556.x) in 2012 with no IBD code or medication from 2008 through 2011. Each case had up to 10 age group, gender, race, and geographically matched controls with no IBD codes, associated diseases or medications. Bariatric surgery was defined as at least one ICD-9 or CPT code for sleeve gastrectomy, roux-en-Y gastroenterostomy, gastric band, or other gastric bypass prior to first IBD code. Past history of bariatric surgery was determined using ICD-9 code V45.86. Patients with history of peptic ulcer disease or malignancy in the esophagus, stomach, small intestine, or pancreas were excluded. Bariatric surgery was evaluated as recent (code in database timeframe), past history (V45.86 code but no bariatric surgery code in database timeframe), or no history. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for new onset IBD, CD and UC. Analyses were adjusted for age, obesity, antibiotics, hormone replacement therapy and statins.
Results: A total of 8,968 cases and 42,929 controls were included in the analysis. Adjusting for potential confounders, any bariatric surgery (combining recent and past history) was associated with significantly increased odds of new IBD (OR 1.46, 95% CI 1.09–1.96). Patients who had recent bariatric surgery (within the 4 years prior to diagnosis) did not appear to be at shorter term risk of IBD (OR 0.95, 95% CI 0.58–1.54). However, past history of bariatric surgery was associated with an increased risk of new onset IBD (OR 1.95, 95% CI 1.36–2.82). This association was stronger for UC than CD (Table 1). Of note, obesity was also associated with new IBD in this cohort (OR 1.50, 95% CI 1.39–1.63).
Conclusions: New onset IBD was significantly associated with past history of bariatric surgery. This potential association should be evaluated in prospective studies.