Overweight and Obese Patients with Ulcerative Colitis (UC): Prevalence and Epidemiology in a University-based Population Cohort

Abstract

Purpose: Obesity in the IBD population has historically been considered to be uncommon. This study aims to determine prevalence of obesity in a university-based cohort of UC patients (pts) and to evaluate whether overweight and obese status is associated with pt demographics or disease characteristics. Methods: All pts with UC seen in our GI division from 6/1/2009 to 6/1/2012 were eligible (n=676) for analysis. EMRs were then reviewed to identify pts who had confirmation of UC on colonoscopy, two recorded weights >1 year apart, and one recorded height. Weights were averaged to calculate BMI (kg/M2). Overall, 404 pt records (59.8%) were included for calculation of obesity prevalence and weight trends in association with history of surgery. Results: In our population, 194 (47.9%) were male. Mean age was 46.0 years (yrs) with mean age of diagnosis of 32.5 yrs. Mean disease duration was 13.5 yrs. Mean BMI was 25.8, compared to 28.6, the national average for American adults, as reported by the CDC. Pts were divided into BMI subcategories based on the WHO's definition of underweight (<18.5), healthy (18.5-24.9), overweight (25.0-29.9), and obese (>30) individuals. There were 12 (3.0%) underweight pts, 192 (47.5%) healthy, 127 (31.4%) overweight, and 73 (18.1%) obese. This is in comparison to national averages reporting 33.3% of American adults overweight, 35.9% obese. There was no difference in rates of IBD-related surgery between those with BMI >25 vs. <25 (21.0% vs. 23.0%, OR 0.888, CI 0.5543-1.4224). In subset analysis, there was no statistical difference between rates of surgery in the underweight vs. healthy (41.7% vs. 21.9%, OR 2.551, CI 0.7702-8.4492), overweight vs. healthy (22.8% vs. 21.9%, OR 1.0569, CI 0.6175-1.8088), or obese vs. healthy (17.8% vs. 21.9%, OR 0.7738, CI 0.388-1.5433). There was also no difference in time to surgery after diagnosis in overweight or obese pts vs. healthy (9.6yrs vs. 7.7yrs, p=0.33711) or underweight vs. healthy (12.8yrs vs. 7.7yrs, p=0.47177). Conclusion: Approximately 1 in 2 adults with UC are overweight or obese, in comparison to 2 in 3 in the general population. There was no difference in rates of surgery between healthy weight and underweight, overweight, or obese pts. These findings differ distinctly from that previously reported by our group in pts with CD (CGH 2006;4(4):482-488). We also previously reported that obese CD patients had a shorter time to surgery after disease diagnosis, which was not found in this UC cohort. It is clear further studies are needed to determine the effects of obesity on the IBD population.