Ozone therapy for the treatment of chronic wounds:

Background

Chronic wounds - wounds that fail to heal through the normal, orderly stages of tissue repair - place a significant and ongoing burden on healthcare systems worldwide. Conditions such as diabetic foot ulcers, venous and arterial leg ulcers, and other slow-healing injuries often resist standard care, leaving patients with prolonged pain, reduced mobility and a heightened risk of infection. Researchers from Griffith University in Australia set out to examine whether ozone therapy - applied topically as a gas, in ozonated water, or as ozonated oil - could offer a meaningful improvement over conventional wound management.

Study design

The authors conducted a systematic review, searching Google Scholar, PubMed and the Cochrane Library, and cross-checking reference lists, for English-language studies testing topical ozone therapy in human patients with chronic wounds. Nine studies met the inclusion criteria, covering a total of 453 participants. Wound types studied included diabetic ulcers (three studies), venous or arterial ulcers (four studies), a gunshot wound (one study) and burns (one study). Ozone was delivered in several ways across the studies, including sealed chambers filled with an oxygen-ozone gas mixture, ozone-oxygen injections, catheter-based application, and ozonated oils applied directly to the wound. Only four of the nine studies were randomised controlled trials; the review authors rated two studies as having a low risk of bias and six as having a moderate risk, largely due to inconsistent blinding and allocation concealment.

Findings

All nine studies reported improved wound closure in patients treated with ozone compared with standard care or baseline measurements. Reported outcomes included full ulcer closure rates 13.6 to 37 per cent higher in ozone-treated groups, and overall wound closure enhanced by 24 to 50 per cent. In the study involving a gunshot wound, 75 per cent of ozone-treated wounds closed compared with 40 per cent in the control group. Calculated effect sizes ranged from moderate to very high across the studies. Several studies also reported reduced pain in patients receiving ozone therapy. No adverse effects were directly attributed to ozone treatment in any of the included studies.

What the authors concluded

The review authors concluded that, while no single trial offers conclusive proof that ozone therapy is superior to standard wound care, the overall body of evidence "consistently favours" its use for chronic wounds. They suggested this points towards a potential role for ozone therapy in mainstream clinical practice, but stated that this depends on further, higher-quality research being carried out first.

Limitations of this study

The included studies varied considerably in treatment duration (two to twenty-two weeks), ozone concentrations (15 to 60 micrograms per millilitre) and how often treatment was applied, making direct comparisons difficult. Only four of the nine studies were randomised controlled trials, and blinding or allocation concealment was inconsistent or unclear in most. No study directly compared gaseous ozone-oxygen application with ozonated oils, so it is not possible to say which delivery method performs best. The Wagner classification scale used to grade diabetic ulcers in several of the included studies has itself been shown to be less reliable than newer classification systems, which may affect how comparable the results are. The authors called for larger, double-blind trials with longer follow-up periods to confirm these findings and assess any long-term risks.