Weight and body mass index patterns in a cohort of patients with inflammatory bowel disease treated with biological agents

Background and Aim: Biological therapies are effective at inducing and maintaining remission in patients with inflammatory bowel disease (IBD). Previous studies have associated tumor necrosis factor-α inhibitors with weight gain. Contrary to conventional beliefs, about a third of patients with IBD are obese. Undesired weight gain in patients with IBD can be associated with increased risk of complications and poor response to therapy. We therefore aimed to examine weight and body mass index (BMI) changes from baseline across different biological classes over time and to assess characteristics and associations of each (sub)group. Methods: In this retrospective study, adult patients with IBD who received any biological therapy for at least 12 months between 2008 and 2020 were identified from prospectively maintained records at two IBD units in Australia. Data collected included demographics; weight and BMI at baseline, 6, 12, 24, and 48 months; IBD type and phenotype; baseline and follow-up endoscopy; baseline hemoglobin, C-reactive protein (CRP) and albumin levels; combination or monotherapy; initial steroid therapy; and frequency of biologic infusion. A linear mixed-effects model was performed for the outcome of weight change from baseline, including the interaction of treatment group and time period. A latent class analysis was then performed, assigning patients to weight trajectory groups, and univariate ordinal logistic regressions were used to explore possible associations between membership of each group (the outcome) against various predictive factors. Results: Of 294 patients (156 female), 165 received infliximab (IFX), 68 adalimumab (ADA), 36 vedolizumab (VDZ), and 25 ustekinumab (UST). There was a trend for weight gain in the whole cohort, with a mean BMI of 26.58 kg/m2 (SD, 6.01) at initiation of biological therapy and 27.08 kg/m2 (SD, 5.37) at 48 months. There was a statistically significant weight gain over time in both the IFX and VDZ groups and in IFX versus ADA and VDZ versus ADA at most time ...