Impact of Obesity on Outcome for Inflammatory Bowel Disease Patients From 2008 Through 2020

The incidence and prevalence of obesity have been rising in the U.S. It is known to affect the course and treatment of a variety of gastrointestinal disorders. It has been proposed to particularly worsen the symptoms of inflammatory bowel disease (IBD) and put patients at risk of treatment failure. Our study seeks to understand better the impact of obesity on morbidity, mortality, hospital length of stay (LOS), and charges in patients with IBD. The National Inpatient Sample (NIS) from 2008 to 2020 was used to identify patients over 18 diagnosed with IBD using the International Classification of Disease (ICD) 9 and 10 codes. Records were weighted per the NIS algorithm to produce accurate population estimates. Patients were classified by obesity status and then analyzed for baseline characteristics such as age, gender, race, insurance status, and various comorbidities. Various primary outcomes were analyzed. Outcomes were compared between groups, and odds ratios (ORs) were calculated using weighted logistic regression. ORs were adjusted for common co-founders. A weighted total of 2,105,418 patients admitted for IBD were included in this study. Of these, 170,475 were obese, and 1,934,943 were not obese. Obese patients were older, more complex (Charlson comorbidity index CCI 2.03 vs. 1.53), and more likely to be female (p<0.01) than non-obese patients. Compared to non-obese patients, IBD patients with obesity had a higher prevalence of coronary artery disease (11.35% vs. 7.87%), hyperlipidemia (29.27% vs. 15.09%), hypertension (45.38% vs. 25.60%), diabetes mellitus type 2 (27.15% vs. 9.38%), congestive heart failure (4.58% vs. 2.35%), gastroesophageal reflux disease (30.73% vs. 17.98%), and CCI (2.03% vs. 1.53%). Obese IBD patients had slightly higher odds of shock (OR 1.228, p<0.05), acute myocardial infarction (AMI, OR 1.692, p<0.01), acute kidney injury (AKI, OR 1.187, p<0.01), and chronic steroid treatment (OR 1.149, p<0.01). Conversely, obese IBD patients had lower odds of intestinal fistula (OR 0.837, CI 0.77-0.91, p<0.001). Obesity poses a diverse set of complications in IBD patients. Our study found that obese patients admitted with IBD had significantly higher odds of shock, AKI, and chronic steroid treatment. Interestingly, these patients were less likely to develop intestinal fistulas. These findings suggest further research into how obesity affects the disease course.