Obesity in Inflammatory Bowel Disease: A Marker of Less Severe Disease

Background: Both obesity and inflammatory bowel disease (IBD) are highly prevalent in Western societies. IBD, including Crohn’s disease (CD) and ulcerative colitis (UC), has been historically associated with cachexia and malnutrition. It is uncertain how obesity, a chronic pro-inflammatory state, may impact the course of IBD. Aim: The aim of this study was to report the prevalence of obesity in patients with IBD in a metropolitan US population and to assess the impact of obesity on disease phenotypes, treatment, and surgical outcomes in IBD patients. Methods: We reviewed the medical records of patients identified from the IBD registries of the Dallas Veterans Affairs Medical Center and Parkland Health and Hospital Systems who were seen from January 1, 2000, to December 31, 2012. Results: Of 581 identified IBD patients, 32.7 % were obese (BMI ≥ 30) and 67.6 % were non-obese (BMI < 30). There were 297 (51.1 %) patients with CD and 284 (48.9 %) patients with UC. The rate of obesity was 30.3 % among CD patients and 35.2 % among UC patients. Overall, obese patients were significantly less likely to receive anti-TNF treatment, undergo surgery, or experience a hospitalization for their IBD than their non-obese counterparts (55.8 vs. 72.1 %, p = .0001). Conclusion: Obesity is highly prevalent in our IBD patients, paralleling the obesity rates in the US population. Clinical outcomes were significantly different in obese versus non-obese patients with IBD. Despite the plausible mechanisms whereby obesity might exacerbate IBD, we have found that obesity (as defined by BMI) is a marker of a less severe disease course in IBD.