High body mass index is associated with increased risk of treatment failure and surgery in biologic‐treated patients with ulcerative colitis

BackgroundThough pharmacokinetic studies suggest accelerated biologic drug clearance with increasing body weight, evidence of obesity's impact on clinical outcomes in biologic-treated patients with ulcerative colitis (UC) is inconsistent.AimTo evaluate the impact of obesity on real world response to biological therapy in patients with UC.MethodsIn a single-centre retrospective cohort study between 2011-2016 of biologic-treated patients with UC, we evaluated treatment response by baseline body mass index (BMI). Primary outcome was treatment failure (composite outcome of IBD-related surgery/hospitalisation or treatment modification including dose escalation, treatment discontinuation or addition of corticosteroids); secondary outcomes were risk of IBD-related surgery/hospitalisation and endoscopic remission. We conducted multivariate Cox proportional hazard analyses to evaluate the independent impact of BMI on clinical outcomes. Stratified analysis by weight-based regimens (infliximab) or fixed-dose regimens (adalimumab, golimumab, vedolizumab, certolizumab pegol) was performed.ResultsWe included 160 biologic-treated UC patients (50% males, 55% on infliximab) with median (IQR) age 36 y (26-52) and BMI 24.3 kg/m2 (21.4-28.7). On multivariate analysis, each 1 kg/m2 increase in BMI was associated with 4% increase in the risk of treatment failure (adjusted hazard ratio [aHR], 1.04 [95% CI, 1.00-1.08]) and 8% increase in the risk of surgery/hospitalisation (aHR, 1.08 [1.02-1.14]). The effect on treatment failure was seen in patients on weight-based dosing regimens or fixed-dose therapies.ConclusionBMI is independently associated with increased risk of treatment failure in biologic-treated patients with UC, independent of dosing regimen