Pediatric perianal Crohn's disease behavior in the era of biologic therapy.

Aim of the study: To describe perianal Crohn's disease behavior and the role of biological therapy in a sample of pediatric patients.

Methods: A retrospective study of pediatric patients with Crohn's disease (CD) treated in our institution from 2017 to 2021, with a minimum follow up period of 6 months, was conducted. Patients were divided whether they had perianal disease (PD) or not. Baseline characteristics, extension of disease, growth failure rate, aggressive pattern rate, use of biological therapy and need for surgery, among other variables, were compared between both groups. Clinical and/or radiological improvement in the last 6 months of follow up was considered good control of PD.

Results: Seventy eight pediatric patients with CD were included. Median age at diagnosis was 10.5 years, and median follow up time was 3.8 years. 64.1% patients were male. Of all, 15 (19.2%) had perianal disease, of which 10 had fistulizing findings and 5 had non fistulizing findings. PD was presented at diagnosis in 8 patients, and the rest developed it in a median time of 1 year from diagnosis. PD was associated with growth failure (p = 0.003), use of biological therapies (p = 0.005), and need for second line of biologics (p = 0.005). Most patients (12/15, 80%) had good control of PD with the treatment received.

Conclusions: CD patients with PD seem to need a more aggressive treatment, with biological therapies playing a key role for its handling nowadays. These patients require close nutritional evaluation that ensures proper development and growth.