Objectives: Prior studies suggest that medication exposures may be associated with new onset inflammatory bowel disease (IBD). The aim of this study was to determine the effect of statins on the risk of new onset IBD in a large United States health claims database.
Methods: We conducted a retrospective matched case-control study with a national medical claims and pharmacy database from Source Healthcare Analytics LLC. We included any patient aged 18 or older with ICD-9 code 555.x for Crohn's disease (CD) or 556.x for ulcerative colitis (UC) between January 2008 and December 2012. IBD patients diagnosed in 2012 were compared with the age group, gender, race, and geographically matched controls. Controls had no ICD-9 codes for CD, UC, or IBD-associated diseases and no prescriptions for IBD-related medications. New onset IBD patients were defined as having at least three separate CD or UC ICD-9 codes and no IBD-related ICD-9 or prescription before first IBD ICD-9. Statin exposure was assessed by Uniform System of Classification level 5 code. To account for diagnostic delay, exposures within 6 months of first ICD-9 were excluded. Exposures within 12 and 24 months were excluded in sensitivity analyses. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for new onset IBD, CD, and UC.
Results: A total of 9,617 cases and 46,665 controls were included in the analysis. Any statin exposure was associated with a significantly decreased risk of IBD (OR 0.68, 95% CI 0.64-0.72), CD (0.64, 95% CI 0.59-0.71), and UC (OR 0.70, 95% CI 0.65-0.76). This effect was similar for most specific statins and regardless of intensity of therapy. The protective effect against new onset CD was strongest among older patients. Statins' association with a lower risk of IBD was similar after adjusting for antibiotics, hormone replacement therapy, oral contraceptives, comorbidities, and cardiovascular medications.
Conclusions: Statins may have a protective effect against new onset IBD, CD, and UC. This decreased risk is similar across most statins and appears to be stronger among older patients, particularly in CD.