Review: In patients with chronic diabetic foot ulcers, hyperbaric oxygen reduces major amputations

Researchers reviewed 13 studies, including seven randomized, controlled trials (RCTs), that compared treatment of chronic diabetic foot ulcers with hyperbaric oxygen (HBO) therapy to treatment without HBO. They found that HBO resulted in more healed ulcers (relative risk [RR], 2.33; 95% CI, 1.51 to 3.60) and fewer major amputations (RR, 0.29; 95% CI, 0.19 to 0.44), but no difference in minor amputations.

The study was published in the February Mayo Clinic Proceedings. The following commentary by M. Hassan Murad, MD, MPH, ACP Member, Qusay Haydour, MD, and Khalid Benkhadra, MD, was published in the ACP Journal Club section of the Aug. 20 Annals of Internal Medicine.

The 7 RCTs summarized by Liu and colleagues show that HBO may increase healing of diabetic foot ulcers and reduce major amputations. Confidence in this evidence is low to moderate, balanced between the inconsistency of results across studies and the small number of events, and the very large (7-fold) effect found for healing rate. Despite the inconsistency, all point estimates for RCTs and observational studies are favorable for HBO and healing (Peto odds ratio 7.57, 95% CI 4.35 to 13.19; Peto odds ratio is a suitable estimate for meta-analyses that include studies with 0 events). Publication bias is a concern when all trials are small and positive. A recent large observational study, however, showed that HBO decreased healing and increased amputations, probably due to selection bias given that the worst, more recalcitrant ulcers are usually referred to HBO. The real effect should be derived from RCTs.

In practice, HBO sometimes works and sometimes not. There are several reasons for the varied responses observed in research and practice. First, a common misconception is that it works alone. HBO is an adjunctive therapy that should be delivered after an individualized approach with other wound care standards (e.g., debridement, revascularization, off-loading). In practice, once patients are referred to HBO, other wound care methods usually stop or decrease in intensity. Second, diabetic foot ulcers have multiple causes (e.g., ischemic, neuropathic, infectious) that affect how we should treat them and how they respond to HBO. Third, HBO is approved by society guidelines and is funded by payers for Wagner III or higher ulcers that have failed 30-day standard therapy. In reality, only recalcitrant cases that have persisted for a much longer time are referred to HBO.

The results of the review by Liu and colleagues are consistent with a beneficial effect in some, but not all, diabetic foot ulcers. We recommend proper evaluation of the patient to establish an individualized diagnostic and treatment strategy that includes HBO. As wound care practitioners say, “Consider the whole patient, not just the hole in the patient.”