Obesity Is Associated with Inferior Clinical Treatment Outcomes in Inflammatory Bowel Disease: A Nationwide Dutch Registry Study

Abstract

Purpose: To examine the impact of obesity on treatment outcomes in inflammatory bowel disease (IBD). Methods: Patients aged ≥ 16 years, with IBD, a documented baseline body mass index (BMI), and starting thiopurines and allopurinol, intravenous (iv) vedolizumab, subcutaneous (sc) vedolizumab, ustekinumab, ozanimod, filgotinib, or tofacitinib were selected from the Dutch Initiative on Crohn and Colitis (ICC) registry. Underweight patients (BMI < 18.5 mg/kg2) were excluded. The primary outcome was steroid-free clinical remission (i.e. Simple Clinical Colitis Activity Index (SCCAI) ≤ 2 for ulcerative colitis (UC) and IBD-unclassified (IBD-U), and Harvey Bradshaw Index (HBI) < 5 for Crohn’s disease (CD)) at week 24. Remission rates were compared between normal weight (BMI 18.5–25 kg/m2), and overweight (BMI 25–30 kg/m2), and obese (BMI ≥ 30 kg/m2) patients using binary logistic regression analyses. Multivariable regression analysis was used to correct for possible confounders. Results: Among 1066 patients with IBD, 619 had normal weight, 303 were overweight, and 144 were obese. At week 24, obese patients achieved steroid-free clinical remission less frequently (35.3%, OR = 0.578, 95% CI: 0.380–0.879, p = 0.010), supported by multivariable analysis (OR = 0.537, 95% CI: 0.346–0.832, p = 0.005). Conclusions: Obesity was associated with lower steroid-free clinical remission at week 24. Obese patients with IBD should be encouraged to lose weight not only to improve their overall health, but also to optimize their treatment outcomes.