The Impact of Obesity on the Prevalence and Complications of Perianal Fistulas of Crohn's Disease.

Background: The incidence of obesity in patients with inflammatory bowel disease (IBD) is increasing and there are limited data on the impact of obesity on perianal fistulas in Crohn's disease (CD).

Aims: We aim to examine the relationship between obesity and the prevalence and complications of Crohn's perianal fistulas.

Methods: We conducted a cross-sectional study of CD patients treated at a tertiary care center from 2012 to 2022. Obesity was defined as maximum BMI > 30 kg/m² and further subdivided into 5 BMI categories. The prevalence of perianal fistulas was defined by any history of perianal fistula. The complications of perianal fistulas were measured by five variables including complex fistulas, history of perianal fistula surgery, number of perianal surgeries, history of fecal diversion, and median time to first anal surgery.

Results: In all, 704 patients with CD were included; 31.1% were obese. There was no significant association between obesity and prevalence of perianal fistulas (p = 0.719), complex fistulas (p = 0.144), history of perianal surgery (p = 0.146), ≥ 1 perianal surgeries (p = 0.220), fecal diversion (p = 0.705), or median time to first perianal surgery (p = 0.192). Increasing BMI category was not associated with the prevalence of perianal fistulas (p = 0.944), complex fistulas (p = 0.089), perianal surgery (p = 0.583), ≥ 1 perianal surgeries (p = 0.114), fecal diversion (p = 0.542), or median time to first perianal surgery (p = 0.486). When comparing those with perianal fistulas to those without, there was no significant difference in rates of obesity (p = 0.876).

Conclusion: There was no association between obesity and the prevalence and complications of Crohn's perianal fistulas.