Hyperbaric oxygen therapy for the treatment of perianal fistulas in 20 patients with Crohn’s disease

BACKGROUND: Positive effects of hyperbaric oxygen on perianal fistulas in Crohn's disease have been reported. AIM: To assess efficacy, safety and feasibility of hyperbaric oxygen in Crohn's disease patients with therapy‐refractory perianal fistulas. METHODS: Twenty consecutive patients were recruited at the out‐patient fistula clinic of the Amsterdam UMC. Crohn's disease patients with high perianal fistula(s) failing conventional treatment for over 6 months were included. Exclusion criteria were presence of a stoma, rectovaginal fistula(s) and recent changes in treatment regimens. Patients received treatment with 40 hyperbaric oxygen sessions and outcome parameters were assessed at Week 16. RESULTS: Seven women and 13 men were included (median age 34 years). At Week 16, median scores of perianal disease activity index and modified van Assche index (co‐primary outcome parameters) decreased from 7.5 (95% CI 6‐9) to 4 (95% CI 3‐6, P < 0.001), and from 9.2 (95% CI 7.3‐11.2) to 7.3 (95% CI 6.9‐9.7, P = 0.004) respectively. Perianal disease activity index scores ≤4 (representing inactive perianal disease) were observed in 13/20 patients (65%). Twelve patients showed a clinical response (60%) and four (20%) clinical remission, assessed with fistula drainage assessment. Median C‐reactive protein and faecal calprotectin levels decreased from 4.2 mg/mL (95% CI 1.6‐8) to 2.2 (95% CI 0.9‐4.3, P = 0.003) and from 399 µg/g (95% CI 52‐922) to 31 (95% CI 16‐245, P = 0.001), respectively. CONCLUSIONS: We found significant clinical, radiological and biochemical improvement in Crohn's disease patients with therapy‐refractory perianal fistulas after treatment with hyperbaric oxygen. Clinical trial registration: www.trialregister.nl/trial/6489.