#4 HBO for DFU with PAD
A systematic review and meta-analysis of hyperbaric oxygen therapy for diabetic foot ulcers with arterial insufficiency
Journal of Vascular Surgery, 2020, Volume 71, Issue 2, Pages 682–692.e1
Robin J. Brouwer, MD, Rutger C. Lalieu, MD, Rigo Hoencamp, MD, PhD, Rob A. van Hulst, MD, Dirk T. Ubbink, MD
While widely used, the use of hyperbaric oxygen therapy has been questioned due to a relative paucity of well controlled trials. I elected to review this article because it provides an up to date look at the evidence regarding hyperbaric oxygen in diabetic foot ulcers with arterial insufficiency.
This systematic review and meta-analysis of hyperbaric oxygen therapy in patients with diabetic foot ulcers follows the Preferred Reporting Items for Systematic reviews in Meta-Analysis (PRISMA) rules for objective review. The authors included studies if they performed hyperbaric oxygen therapy in patients with diabetes mellitus, peripheral arterial disease and leg ulcer in addition to standard treatment regimens. Studies that included both patients with and without peripheral arterial disease were excluded from analysis if there was no sub group data on ischemic diabetic foot ulcers. They define peripheral arterial disease as having an ankle brachial index of <= 0.9, a toe brachial pressure index <= 0.7, a toe pressure < 30 mm Hg or transcutaneous oximetry on the dorsum of the foot < 30 mm Hg.
A total of 11 studies were included in the qualitative analysis. Of these, seven were randomized controlled trials, two were controlled clinical trials, and two were retrospective cohort studies. Most of the studies used a protocol of 90 minutes of hyperbaric oxygen therapy with pressures between 2.2 and 2.8 ATA for 5 to 7 days per week with an aim to total 20 to 60 sessions. Three of the studies used hyperbaric oxygen therapy until the wounds were completely healed. Follow up time vary between two weeks and three years and study sizes varied between 18 and 120 patients. Only four of the studies had data for an ischemic subgroup which allowed for meta-analysis.
The meta-analysis showed that the rate of major amputation was significantly lower in the group treated with hyperbaric oxygen therapy 10.7% compared to the control group 26.0% (P = 0.002, number needed to treat (NNT) = 7. Minor amputation rates did not differ significantly, P = 0.46. There was no significant differenced seen for healing time or mortality. Adverse events were found in one patient who developed cataracts, one patient with middle ear barotrauma and ear pain which diminished with local treatment with decongestant, three patients required myringotomy, one patient had an oxygen induced seizure, two cases of barotraumatic otitis and one case of middle ear perforation.
The authors concluded that this first systematic review focusing specifically on patients with diabetic foot ulcer and peripheral arterial disease did show that hyperbaric oxygen therapy as an adjunct a standard wound care in this subset of patients did lead to a decrease in major amputation but had no difference in minor amputation rate, mortality, or healing time. They found the number needed to treat to prevent one major amputation was only seven patients.
My interpretation: This systematic review and meta-analysis does support the use of hyperbaric oxygen therapy in patients with diabetic foot ulceration and peripheral arterial disease. The main reason hyperbaric oxygen therapy is offered to patients with diabetic ulcers is to prevent major amputation. Given the reported 5-year mortality rate of 40% or more for patients who require below the knee amputation, a number needed to treat of seven with no life-threatening adverse events indicates that hyperbaric oxygen therapy should be offered to appropriate patients with diabetic foot ulceration and peripheral arterial disease. Of course, it would be nice if we had double-blind placebo controlled randomized trials with large numbers of patients. Large trials would be able to better answer the question regarding hyperbaric oxygen therapy effects on healing rates, mortality, and amputation. This meta-analysis was not able to show any significant difference in all but major amputation, but the difference shown in major amputation is significant enough that even if there was no difference in healing rates or minor amputation, hyperbaric oxygen therapy would still be indicated.