Hyperbaric oxygen therapy yielded a clinical response rate of 87% among patients with fistulizing Crohn’s disease with few adverse events, according to systematic review data presented at the Crohn’s and Colitis Congress.

“Fistulas are a common complication of Crohn’s disease occurring in up to 50% of patients,” Amr Dokmak, MD, a hospitalist at Catholic Medical Center in Manchester, New Hampshire,told Healio. “Despite significant expansion of the IBD therapeutics, particularly biologics and innovations in treatment strategy, there remains a significant gap in achieving long-standing fistula healing. Hyperbaric oxygen therapy has gained interest as a potential adjunct therapy for refractory IBD.”

To determine whether there is sufficient evidence in the literature for the effective and safe use of hyperbaric oxygen in fistulizing CD, Dokmak and colleagues conducted a systematic review of EMBASE, Web of Science, PubMed and Cochrane Library databases. The researchers included published articles and abstracts if they met study design criteria, evaluated hyperbaric oxygen efficacy in patients with fistulizing CD and reported sufficient outcome data, which were measured clinically, radiographically and/or endoscopically.

Dokmak and colleagues included 16 studies in their analysis, consisting of 164 patients who underwent 5,125 hyperbaric oxygen therapy sessions. Their primary interest was in overall clinical response — defined as either clinical remission or partial response — with hyperbaric oxygen therapy. The researchers specified clinical remission as closure of fistula and complete cessation of drainage, and partial response as improvement in fistula drainage.

“Our systematic review demonstrated a pooled overall clinical response rate of 87%, suggesting that hyperbaric oxygen therapy may be an effective treatment option for fistulizing disease,” Dokmak said. “[However] rectovaginal fistulas were the fistula subtype least responsive to hyperbaric oxygen therapy.”

In addition, the researchers reported a pooled clinical remission of 59% (95% CI, 0.35-0.8) among patients who received hyperbaric oxygen therapy. The pooled number of adverse events was minimal at 51.7 per 10,000 hyperbaric oxygen therapy sessions across all fistula types (95% CI, 16.8-159.3).

However, as Dokmak noted, the overall clinical response varied by subtype, with perianal fistulas being most responsive (89%) to therapy, followed closely by enterocutaneous fistulas (84%); patients with rectovaginal fistulas experienced the lowest response to therapy (29%).

The researchers reported that hours in the oxygen chamber or the number of hyperbaric oxygen therapy sessions was not associated with an enhanced clinical response.

“Hyperbaric oxygen therapy is a safe and potentially effective treatment option for fistulizing Crohn’s disease,” Dokmak told Healio. “[However,] randomized control trials are needed to substantiate the benefit of hyperbaric oxygen therapy in fistulizing Crohn’s disease.”