Diabetic foot ulcers are among the most serious complications of diabetes, and a substantial proportion fail to heal with standard wound care alone — particularly when reduced blood flow to the lower limb is involved. For these difficult, non-healing wounds, clinicians have long searched for adjunctive treatments that can tip the balance toward healing and away from amputation. Hyperbaric oxygen therapy (HBOT) is one of the most studied, and most debated, of these options. Understanding what the research actually shows helps patients, caregivers, and healthcare professionals interpret a therapy that is often surrounded by both enthusiasm and skepticism.
How Hyperbaric Oxygen Therapy Works
HBOT involves breathing 100% oxygen while inside a pressurized chamber, typically at two to two-and-a-half times normal atmospheric pressure. Under these conditions, the amount of oxygen dissolved in the blood plasma rises sharply, raising oxygen delivery to tissues well beyond what breathing room air can achieve. In a chronic diabetic foot wound — where tissue oxygen levels are often low because of impaired circulation and microvascular disease — this temporary surge in oxygenation is thought to support several healing processes. It can promote the formation of new blood vessels (angiogenesis), enhance the ability of white blood cells to fight infection, reduce tissue swelling, and stimulate the fibroblasts and growth factors involved in building new tissue. A typical treatment course involves daily sessions over several weeks, with each session lasting roughly 90 to 120 minutes.
What the Clinical Evidence Shows
The evidence on HBOT for diabetic foot ulcers is genuinely mixed, which is why it remains a subject of ongoing discussion. A 2015 Cochrane systematic review by Kranke and colleagues found that HBOT improved the likelihood of ulcer healing in the short term — at around six weeks — but the reviewers noted that this benefit was not clearly sustained at longer-term follow-up, and that many of the available trials were small and at risk of bias.
More recent meta-analyses have reported more favourable results. A 2024 systematic review and meta-analysis based on Wagner ulcer grading by Oley and colleagues, which pooled 14 randomized controlled trials, found moderate-quality evidence that adjunctive HBOT significantly improved healing rates for moderate-to-severe ulcers (Wagner grades II–IV) and reduced the need for both minor and major amputations in more severe cases, without notable adverse effects. A separate 2021 meta-analysis of controlled clinical trials by Sharma and colleagues, which included 14 studies and 768 participants, similarly concluded that HBOT was significantly effective for complete ulcer healing and for reducing major amputations — although it did not find a clear benefit for minor amputations. The fact that these reviews do not agree on every outcome reflects real differences in patient populations, ulcer severity, and trial quality, and is an important reason that conclusions about HBOT have varied over time.
The DAMO2CLES Trial
One of the most important and sobering studies is the DAMO2CLES multicenter randomized clinical trial, published in Diabetes Care in 2018 by Santema and colleagues. This trial randomized 120 patients who had diabetes, a foot ulcer, and concurrent lower-limb ischemia to standard care with or without HBOT. The investigators found that adding HBOT did not produce statistically significant improvements in limb salvage or wound healing. The trial also documented two serious treatment-related adverse events — an oxygen-induced seizure and a barotraumatic perforation of the eardrum — though both patients recovered fully. DAMO2CLES is frequently cited as a reminder that HBOT is not a guaranteed solution, even in the ischemic wounds where its physiological rationale is strongest.
Where Clinical Guidelines Currently Stand
Reflecting this uncertainty, the 2023 International Working Group on the Diabetic Foot (IWGDF) guideline on interventions to enhance wound healing takes a measured position. It suggests that HBOT may be considered as an adjunctive treatment for neuro-ischemic or ischemic diabetic foot ulcers that have failed to heal with optimal standard care, and only where the resources to deliver it safely are already available. Importantly, the same guideline recommends against using HBOT for the sole purpose of treating a diabetes-related foot infection. In other words, HBOT is positioned as a selective add-on for a specific subset of non-healing wounds — not a routine or first-line therapy.
Safety and Practical Considerations
HBOT is generally well tolerated, but it is not without risk. Recognized complications include middle-ear barotrauma, temporary changes in vision, claustrophobia, and, rarely, oxygen-induced seizures. The therapy is also resource-intensive: it requires specialized chambers, trained staff, and a significant time commitment from patients attending daily sessions over several weeks. These practical factors, alongside the mixed efficacy data, explain why careful patient selection — focusing on non-healing ischemic or neuro-ischemic ulcers after standard care has been optimized — is central to current recommendations.
Key Clinical Takeaways
Hyperbaric oxygen therapy remains a legitimate but limited tool in diabetic foot care. The collective evidence suggests it can improve healing and reduce amputations for certain moderate-to-severe, non-healing ulcers, while high-quality trials such as DAMO2CLES caution against expecting benefit in every ischemic wound. Current guidelines support its use only as a carefully selected adjunct after standard wound care, offloading, infection control, and vascular assessment have been addressed. For patients and clinicians alike, the central message is that HBOT is best understood as one component of comprehensive, multidisciplinary diabetic foot management rather than a stand-alone cure.
References
- Kranke P, Bennett MH, Martyn-St James M, Schnabel A, Debus SE, Weibel S. Hyperbaric oxygen therapy for chronic wounds. Cochrane Database of Systematic Reviews. 2015;(6):CD004123.
- Santema KTB, Stoekenbroek RM, Koelemay MJW, et al. Hyperbaric Oxygen Therapy in the Treatment of Ischemic Lower-Extremity Ulcers in Patients With Diabetes: Results of the DAMO2CLES Multicenter Randomized Clinical Trial. Diabetes Care. 2018;41(1):112–119.
- Sharma R, Sharma SK, Mudgal SK, Jelly P, Thakur K. Efficacy of hyperbaric oxygen therapy for diabetic foot ulcer, a systematic review and meta-analysis of controlled clinical trials. Scientific Reports. 2021;11:2189.
- Oley MH, Oley MC, Kepel BJ, et al. Hyperbaric Oxygen Therapy for Diabetic Foot Ulcers Based on Wagner Grading: A Systematic Review and Meta-analysis. Plastic and Reconstructive Surgery – Global Open. 2024;12(3):e5692.
- Chen P, et al., on behalf of the International Working Group on the Diabetic Foot (IWGDF). Guidelines on interventions to enhance healing of foot ulcers in people with diabetes (IWGDF 2023 update). Diabetes/Metabolism Research and Reviews. 2024;40(3):e3644.
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