Abstract
INTRODUCTION: We conducted a cohort study on the impact of obesity on disease activity and Patient-Reported Outcomes Measurement Information System (PROMIS) measures in the inflammatory bowel disease (IBD) Partners cohort. METHODS: We performed a cross-sectional and longitudinal study within IBD Partners, an internet-based cohort of >15,000 patients living with Crohn's disease (CD) and ulcerative colitis (UC). We included adult patients with IBD, with recorded body mass index (BMI), with at least 6 months of follow-up, excluding patients with BMI < 18.5 kg/m. We evaluated the independent effect of World Health Organization classes of obesity on risk of clinical relapse or persistent disease activity (using validated disease activity indexes) and PROMIS measures, using multivariate logistic regression and linear regression, respectively. RESULTS: We included 7,296 patients with IBD (4,748 patients with CD, 19.5% obese; 2,548 patients with UC with intact colon, 20.3% obese). Obesity was independently, and in a dose-dependent fashion, associated with an increased risk of persistent disease activity or relapse in both patients with CD (class II or III obesity vs normal BMI: adjusted odds ratio, 1.86; 95% confidence interval, 1.30-2.68) and UC (adjusted odds ratio, 2.97; 95% confidence interval, 1.75-5.17). Obesity was also independently associated with higher anxiety, depression, fatigue, pain, and inferior social function scores in patients with CD and UC at baseline and with worsening depression, fatigue, pain, and social function in patients with CD on longitudinal assessment. DISCUSSION: Obesity at baseline is independently associated with worsening disease activity and PROMIS measures in patients with IBD.