Prevalence and factors associated with obesity in patients with inflammatory bowel disease (IBD) treated with infliximab and vedolizumab across the UK

Objectives Obesity is associated with worse treatment outcomes in patients with IBD. We sought to define in an adult and paediatric population of people living with IBD treated with either infliximab or vedolizumab who were recruited to the UK CLARITY IBD to study the: 1. Prevalence of overweight and obesity. 2. Demographic, geographic and disease factors associated with obesity. 3. Influence of obesity on mood, anxiety and IBD related quality of life. 4. Relationship between obesity and geographical determinants of health. Methods Obesity in adults was defined according to the World Health Organization (WHO) body mass index (BMI) definitions, and obesity in children (<19 years) was defined according to the UK-WHO growth charts. Mood and anxiety disorders were assessed using the Patient Health Questionnaire and General Anxiety Disorder Assessment. We extracted deprivation decile from the index of multiple deprivation and geographical determinants of health data from the Access to Healthy Assets and Hazards (AHAH) (Version 4). Results Overall, 31.3% (2147/6864 95% CI 30.2 to 32.4) and 24.6% (1691/6864 95% CI 23.6 to 25.7) patients were overweight and obese, respectively. The highest prevalence of obesity was observed in the East Midlands and the lowest prevalence in London. Multivariable logistic regression analysis demonstrated that obesity was independently associated with female sex, older age, non-Asian ethnicity, no prior IBD surgery and symptoms of active disease. Obesity in adults was associated with depression but not anxiety. Obesity was significantly associated with higher deprivation scores. Discussion Obesity is common in UK patients living with IBD and is independently associated with female sex, older age, non-Asian ethnicity, geographical region, active IBD symptoms, depression, deprivation and poorer air quality.