Introduction: Research in hyperbaric oxygen (HBO) medicine is growing, but the quality of HBO studies is variable. Low study quality may compromise evidence-based decision-making and clinical translation.

Methods: This cross-sectional study examined the adherence of 50 randomly selected HBO clinical trials (25 randomised controlled trials [RCTs] and 25 observational studies) to relevant core reporting guidelines: consolidated standards of reporting trials (CONSORT), non-pharmacologic treatments (NPT), and strengthening the reporting of observational studies in epidemiology (STROBE). Studies published in peer-reviewed journals between January 2018 and May 2023 and indexed on PubMed were analysed. Reporting quality was classified as 'excellent' (> 85% of guideline items adequately reported), 'good' (50-85%), or 'poor' (< 50%).

Results: The sample represented 29% of RCTs and 16% of observational studies for the timeframe assessed. No study was rated as 'excellent' for completeness, 28 (56%) were rated as 'good', and 22 (44%) as 'poor'. In RCTs, only one study (4%) adequately reported protocol adherence and eight studies (32%) reported blinding procedures. The NPT checklist showed that key items, including care provider adherence (0 studies) and participant adherence (one study; 4%), were frequently not reported. For observational studies, basic design elements were adequately reported, but with significant gaps in bias management (nine studies; 36%) and missing data handling (13 studies; 52%). Only six studies (12%) mentioned the use of reporting guidelines.

Conclusions: Our results showed that quality of reporting of HBO studies is suboptimal. These findings highlight the need for increased awareness and implementation of reporting guidelines, as well as the potential development of HBO-specific guidelines.