Gender Differences and Other Factors Associated with Weight Gain Following Initiation of Infliximab: A Post Hoc Analysis of Clinical Trials

Background In our clinical practice, women often report excess weight gain with infliximab (IFX) use. There are currently no studies investigating weight gain after antitumor necrosis factor therapy in patients with inflammatory bowel disease. The objective of this study was to evaluate the association of clinical factors, with a particular focus on sex and weight gain in patients with moderate to severe Crohn's disease (CD) or ulcerative colitis (UC) initiating IFX. Methods Data was extracted from ACCENT I, ACCENT II, ACT 1, and SONIC; included patients received IFX for induction or maintenance of remission of CD or UC. Patients treated with azathioprine (IFX 0 mg/kg) were included as controls. Baseline demographics, clinical characteristics, and weight at each follow-up for the study duration were collected. In addition to descriptive statistics, adjusted mixed effects models were used to test the association between clinical variables and weight gain. Results There were 1273 patients included for analysis; the majority was white (91%), with CD (81%), and half of patients (50%) were women. Upon univariate analysis, IFX dose, African American race, diagnosis of CD, elevated C-reactive protein, and low hematocrit and albumin were associated with weight gain (P < 0.001). Upon adjusted analysis, sex was significantly associated with weight gain (P = 0.009), with women experiencing a lower percentage increase from baseline weight than men (3.9% increase vs 4.3% increase). Conclusions When starting IFX, those with markers of severe disease and with a diagnosis of CD are likely to gain more weight. Adjusting for confounding variables, women actually gain less weight than men after IFX treatment, although this difference is not clinically relevant.