Hyperbaric oxygen therapy (HBOT) can help heal bowel fistulas in patients with advanced Crohn’s disease, according to a systematic review and meta-analysis.

Overall, use of HBOT was associated with a 87% clinical response rate for all fistula subtypes, with more than half of the patients achieving clinical remission, or closure of the fistula and complete cessation of drainage, according to Amr Dokmak, MD, of Catholic Medical Center in Manchester, New Hampshire.

In 16 studies, clinical responses were observed in 135 of 164 patients who underwent more than 5,000 HBOT sessions, he reported at the Crohn’s and Colitis Congressopens in a new tab or window.

“With a pooled overall clinical response rate of 87% and a low adverse event [AE] rate, our review emphasizes the potential clinical benefit and safety of adjunctive hyperbaric oxygen therapy in refractory cases of fistulizing Crohn’s disease,” Dokmak and colleagues stated in their abstract.

However, the analysis was limited by the heterogeneity of the studies and lack of control groups so “randomized control trials [RCT] are needed to substantiate the benefit of hyperbaric oxygen therapy in fistulizing Crohn’s disease,” Dokmak stated.

Syed Adeel Hassan, MD, of the University of Kentucky in Lexington, told MedPage Today that “treating fistulizing disease is very daunting for physicians because usually the only treatment is surgery. Our goal as physicians is to try to treat patients to prevent these fistulas — basically holes in the bowel — from occurring in the first place.”

“Hyperbaric oxygen therapy has been used for a variety of conditions, including things like infections, and this study indicates it can be useful in cases of refractory fistulizing Crohn’s disease,” added Hassan, who was not involved in the study.

He agreed that an RCT would be important to sort out exactly how useful HBOT could be. Hassan also noted that in many parts of the world, including his native Pakistan, access to HBOT devices was sorely limited.

And “the researchers need to look into the mechanisms of action as to why hyperbaric oxygen would benefit these patients,” Hassan suggested.

Dokmak’s group considered data sufficient for their analysis if outcomes were measured clinically, radiologically, or endoscopically. Of the 16 studies, there were four single-case reports, and the largest study had 37 patients who averaged 30.2 HBOT sessions each, they reported.

Among 12 studies (single-case reports excluded), clinical response was reported among 131 of 160 patients; clinical remission was reported in 83 of 139 cases in 10 studies.

The researchers also analyzed outcomes based on the type of fistula. They reported that in 15 studies, the clinical response was seen in 115 of 130 patients diagnosed with perianal fistulas, and that in 13 studies, clinical remission was achieved in 68 of 113 patients with perianal fistulas. In 13 studies where patients who had undergone J-pouch surgery were excluded, the rate of clinical response was seen in 89 of 100 cases, while clinical remissions was observed in 50 of 83 cases (n=11 studies).

Among patients who were diagnosed with enterocutaneous fistulas, clinical response was observed in 21 of 25 cases (n=5 studies) while clinical remission was observed in 14 of 19 cases (n=4 studies).

And among patients who were diagnosed with rectovaginal fistulas, clinical response and remission were seen in four of 14 cases (n=5 studies). Dokmak noted that “rectovaginal fistulas were the fistula type least responsive to hyperbaric oxygen therapy.”

The overall clinical response was 89%, 84%, and 29% for perianal, enterocutaneous, and rectovaginal fistulas, respectively, according to the researchers.

They looked at clinical response rates based on whether patients were treated in the biologic or pre-biologic setting, but there were no significant differences in the time analysis, except for patients with rectovaginal fistula who appeared to do better in the pre-biologic era with a 52% clinical response rate and a 25% response rate in the biologic era.

The pooled number of AEs was low at about 51 per 10,000 HBOT sessions, with aural barotraumaopens in a new tab or window as the most reported AE, according to Dokmak and colleagues.

Cited by: MedPage Today