Point-Counterpoint: HBOT: Is It Worthwhile For DFUs?
The authors studied 94 patients with Wagner grade 2, 3 or 4 ulcers, which had been present for more than three months.8 In the intention-to-treat analysis, complete healing of the index ulcer occurred in 37 patients at one year of follow-up: 25/48 (52 percent) in the HBOT group and 12/42 (29 percent) in the placebo group. In a sub-analysis of those patients completing more than 35 HBOT sessions, healing of the index ulcer occurred in 23/38 (61 percent) in the HBOT group and 10/37 (27 percent) in the placebo group. The study authors concluded that adjunctive treatment with HBOT facilitates healing of chronic foot ulcers in selected patients with diabetes. However, it is clear that healing 52 percent of the ulcers in one year does not compare to other studied treatment modalities that use 12 and 20 weeks as the goal for time to heal.
Currently, the highest medical evidence are two meta-analyses, one systematic review and a pragmatic type study. In 2012, an RCT-based meta-analysis focused on the efﬁcacy of HBOT.9 The authors found seven RCTs of 369 subjects that evaluated the efﬁcacy of HBOT in comparison with conventional therapy. Hyperbaric therapy varied from 2 to 3 atm for 45 to 120 min, administered once or twice per day, four to five times per week. The case deﬁnition for diabetic foot ulcer varied across studies but mostly included wounds below the ankle in individuals with diabetes. The wound grade varied from Wagner grade 0 to 4 with most studies including individuals with grade 2 wounds and allowing individuals with poor lower extremity arterial blood ﬂow. The conventional therapy arm also varied by trial but usually involved offloading the foot.
The results did not show an advantage of HBOT in comparison with standard therapy with respect to a healed wound at six months or one year.9 In five trials with a total of 309 patients, the authors also were not able to show fewer amputations, fewer minor amputations or fewer major amputations in those who received HBOT in comparison with standard therapy. Although the study could not show a statistically signiﬁcant advantage, in most circumstances, HBOT appeared to be superior to conventional therapy.
A Closer Look At Two Studies That Cast Doubt On HBOT
In a more pragmatic type study, Margolis and colleagues studied 6,259 individuals with diabetes, adequate lower limb arterial perfusion and foot ulcer extending through the dermis, representing 767,060 person-days of wound care.10 In the propensity score–adjusted models, individuals receiving HBOT were less likely to have healing of their foot ulcer and more likely to have an amputation. Additional analyses, including the use of an instrumental variable, assessed the robustness of the results to unmeasured confounding factors. Hyperbaric oxygen did not improve the likelihood that a wound might heal or decrease the likelihood of amputation in any of these analyses.
In 2013, a systematic review assessed the efﬁcacy and safety of HBOT as adjunctive treatment for diabetic foot ulcers.7 The authors found 13 trials (a total of 624 patients), including seven prospective randomized trials. In regard to short-term healing of diabetic foot ulcers, the overall pooled data revealed a statistically signiﬁcant beneﬁcial effect in HBOT-treated cases but there was a great deal of heterogeneity. Eleven trials assessed the impact of HBOT in preventing major amputation. The study authors found there were signiﬁcantly fewer major amputations in patients undergoing HBOT in comparison to those receiving conventional therapy without HBOT. The study authors detected no heterogeneity.