Impact of Obesity on the Course of Inflammatory Bowel Disease

Background:
The prevalence of obesity has increased substantially in patients with inflammatory bowel disease (IBD), potentially impacting the management and natural history of the disease in these patients. It is hypothesized that obesity may play a pathogenic role in IBD, where excess adipose tissue could secrete a multitude of pro-inflammatory cytokines and, at the same time, act as a reservoir of immune cells, which are fundamental to the development of IBD. We aimed to evaluate the clinical characteristics and clinical e surgical outcomes on obese patients with IBD compared to non-obese IBD patients.
Methods:
This is a retrospective observational cohort study involving adult patients with IBD who were followed up at a tertiary IBD center from January 2019 to August 2023. Epidemiological, clinical, and disease-related data were collected from electronic medical records. Obesity was defined by a body mass index (BMI) ≥ 30 kg/m². We compared between the groups the annual disease activity, need for biological therapy, hospitalization rates, and intestinal surgery over 5 years, postoperative complications, and the occurrence of severe or opportunistic infections. For data analysis, patients were divided into 2 groups: obese and non-obese. Student’s t-test, Chi-square, or Fisher’s exact test were used for data comparison.
Results:
A total of 431 patients with IBD were included. Of these, 116 patients (26.9%) were obese, 60.1% were female, 68.9% had Crohn’s disease, 31.1% had ulcerative colitis, and the mean disease duration was 12.4 ± 10.3 years. There was no statistically significant difference between obese and non-obese patients regarding the type of IBD, disease duration, presence of perianal disease, extraintestinal manifestations, need for intestinal resection, postoperative complications, occurrence of severe or opportunistic infections, and need for biological therapy. Similarly, there was no difference between the groups in disease activity during follow-up in patients with ulcerative colitis. Conversely, obese patients were more frequently women than men (72.4% vs 27.6%, respectively; p=0.001). Additionally, obese patients with Crohn’s disease showed more disease activity during 4 years of follow up and a higher likelihood of having colitis compared to non-obese patients (p=0.002).
Conclusions:
Patients with IBD and obesity were predominantly female. Those with Crohn’s disease and obesity had a higher prevalence of colitis and experienced a more active disease course during follow-up, suggesting that obesity may be an unfavorable factor in the control of Crohn’s disease.