Risk Factors Associated with the Development of Anorectal Fistula after Drainage of an Anorectal Abscess

Introduction: Anorectal abscess is a common surgical condition, and its main complication is anal fistula, which significantly affects quality of life. Objective: To identify risk factors associated with anal fistula development after anorectal abscess drainage. Material and methods: An observational, retrospective, analytical, and cross-sectional study was conducted in 215 patients treated between March 2022 and March 2024. Sociodemographic, clinical, metabolic, and therapeutic variables were analyzed. Bivariate analysis and multivariate binary logistic regression were performed to identify independent risk factors. Results: A total of 193 patients (89.8%) developed anal fistula. In the multivariate analysis, spontaneous drainage was identified as the main independent risk factor (OR = 9.28; 95% CI: 3.61–23.87; p < 0.001). Body mass index was also significantly associated, showing a 13% increase in risk per additional unit (OR = 1.13; 95% CI: 1.01–1.27; p = 0.045). Conclusions: Spontaneous drainage and increased body mass index are independent risk factors for anal fistula development after anorectal abscess drainage.