LAUSR

Objectives: Perianal fistulas are among the most severe complications of Crohn disease, but limited data regarding their outcomes are available in children. Our objective was to determine predictors of perianal fistula healing among pediatric patients newly diagnosed with Crohn disease. Methods: This single-center retrospective study followed patients with perianal fistulas at Crohn disease diagnosis until fistula healing. Time to healing was analyzed using Cox proportional hazard regression models considering relevant covariates including patient demographics, disease characteristics, medical therapies [no anti-tumor necrosis factor (TNF)α therapy, anti-TNFα therapy ±therapeutic drug monitoring], and perianal surgical procedures including fistulotomy, fistulectomy, removal of perianal lesions, seton placement, and incision and drainage. Results: Of 485 patients identified, 107 (22%) had a perianal fistula at Crohn disease diagnosis. Multivariate analysis identified that perianal fistulotomy, fistulectomy, and lesion removal [hazard ratio (HR) 0.46; P = 0.028], non-White race (HR 0.30, P < 0.01), and male sex (HR 0.42; P = 0.02) were associated with delayed fistula healing. Faster fistula healing was associated with treatment with anti-TNFα with therapeutic drug monitoring (HR 1.78, P = 0.009). There were no other differences in healing by treatment. Conclusions: Fistulotomy, fistulectomy, and perianal lesion removal as well as non-White race were associated with delayed fistula healing. Anti-TNFα therapy was associated with faster fistula healing when combined with therapeutic drug monitoring, compared to all other medical treatment groups, including anti-TNFα therapy without therapeutic drug monitoring.