Positive airway pressure therapy and all-cause and cardiovascular mortality in people with obstructive sleep apnoea: a systematic review and meta-analysis of randomised controlled trials and confounder-adjusted, non-randomised controlled studies.

backgroundData regarding the effect of positive airway pressure (PAP) therapy for obstructive sleep apnoea (OSA) on all-cause mortality are inconsistent. We aimed to conduct a systematic review and meta-analysis to test the hypothesis that PAP therapy is associated with reduced all-cause and cardiovascular mortality in people with OSA.

methodsFor this systematic review and meta-analysis, we searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials, from database inception to Aug 22, 2023 (updated Sept 9, 2024), with no language or geographical restrictions. Reference lists of eligible studies and recent conference abstracts (2022-23) were also reviewed. We included outpatient studies (randomised controlled trials [RCTs] or confounder-adjusted, non-randomised controlled studies [NRCSs]) assessing the incidence of all-cause mortality, cardiovascular mortality, or both in adults (aged ≥18 years) with OSA who were treated versus not treated with PAP; other study types and studies that evaluated only PAP adherence were excluded. Abstracts of all retrieved publications were independently screened by two of three researchers (BS, SRB, and KCW), with disagreements resolved by adjudication from another researcher (SHM). The AutoLit feature of the Nested Knowledge platform was used for the review and data-extraction phases. We analysed each log-transformed hazard ratio (HR) and SE using a linear random-effects model to estimate overall HRs and 95% CIs. To evaluate the risk of bias, we used the Cochrane Risk of Bias tool for RCTs and the Newcastle-Ottawa Scale for NRCSs. This study was registered with PROSPERO, CRD42023456627.

findingsOf 5484 records identified by our search, 435 were assessed for eligibility and 30 studies were included in the systematic review and meta-analysis (ten RCTs and 20 NRCSs). These studies included 1 175 615 participants, of whom 905 224 (77%) were male and 270 391 (23%) were female (SE 1·9), with a mean age of 59·5 (SE 1·4) years and a mean follow-up of 5·1 (0·5) years. The risk of bias was low to moderate. The risk of all-cause mortality (HR 0·63, 95% CI 0·56-0·72; p<0·0001) and cardiovascular mortality (0·45, 0·29-0·72; p<0·0001) was significantly lower in the PAP group than in the no-PAP group, and the clinically relevant benefit of PAP therapy increased with use.

interpretationOur results are consistent with a potentially beneficial effect of PAP therapy on all-cause and cardiovascular mortality in patients with OSA. Patients should be made aware of this effect of their treatment, which could result in greater acceptance of treatment initiation and greater adherence, leading to a higher likelihood of improved outcomes.

fundingResMed.