Background and Aims: To assess whether obesity may affect natural history of inflammatory bowel diseases (IBD), we conducted an individual participant data (IPD) pooled analysis of placebo arms, using data from clinical trials of infliximab in IBD, using the Yale Open Data Access (YODA) Project. Methods: We obtained IPD from 4 placebo-controlled trials of infliximab in adults with IBD (ACCENT-I and -II, ACT-1 and -2). Patients were categorized into quartiles based on body mass index (BMI) or weight at time of trial entry. Primary outcome was clinical remission (Crohn’s disease activity index [CDAI]<150, Mayo Clinic Score <3); secondary outcomes were clinical response and mucosal healing. Using multivariable logistic regression analysis, we compared association between quartiles of BMI (or weight) and achieving remission, after adjusting for sex, smoking, disease activity, and concomitant prednisone and/or immunomodulators. Results: We included 575 placebo-treated patients (mean age 38y, 51.6% males, 16% obese). Obesity was not associated with odds of achieving clinical remission (Q4 vs. Q1: adjusted OR, 1.36 [95% CI, 0.65-2.89], p-value for trend=0.57), clinical response (Q4 vs. Q1: adjusted OR, 1.31 [0.61-2.81], p=0.45) or mucosal healing remission (Q4 vs. Q1: adjusted OR, 0.55 [0.12-2.34], p=0.31). These results were consistent across strata based on disease type (CD and ulcerative colitis) and trial design (induction and maintenance therapy). Conclusions: Based on IPD pooled analysis of placebo arms, obesity does not significantly impact short- and intermediate-term clinical outcomes in patients with IBD. Impact of obesity on long-term patient-important outcomes like surgery and hospitalization merits evaluation.
