Long-term effects on clinical event, mental health, and related outcomes of CPAP for obstructive sleep apnea: a systematic review.

STUDY OBJECTIVES:Systematic review of long-term health outcomes of continuous positive airway pressure (CPAP) use in adults with obstructive sleep apnea. METHODS:We updated prior systematic reviews with searches in multiple databases through January 3, 2023. We included randomized controlled trials (RCTs) and adjusted nonrandomized comparative studies (NRCSs) that reported specified long-term (mostly >1 year) health outcomes. We assessed risk of bias, conducted meta-analyses, and evaluated strength of evidence. RESULTS:We found 38 eligible studies (16 trials, 28 observational). All conclusions were of low strength of evidence given study and data limitations. RCTs found no evidence of effect of CPAP on mortality (summary effect size [ES] 0.89; 95% CI 0.66, 1.21); inclusion of adjusted NRCSs yields an association with reduced risk of death (ES 0.57; 95% CI 0.44, 0.73). RCTs found no evidence of effects of CPAP for cardiovascular death (ES 0.99; 95% CI 0.64, 1.53), stroke (ES 0.99; 95% CI 0.73, 1.35), myocardial infarction (ES 1.05; 95% CI 0.78, 1.41), incident atrial fibrillation (ES 0.89; 95% CI 0.48, 1.63), and composite cardiovascular outcomes (all statistically nonsignificant). RCTs found no evidence of effects for incident diabetes (ES 1.02; 95% CI 0.69, 1.51) and accidents (all nonsignificant), and no clinically significant effects on depressive symptoms, anxiety symptoms, or cognitive function. CONCLUSIONS:Whether CPAP use for obstructive sleep apnea affects long-term health outcomes remains largely unanswered. RCTs and NRCSs are inconsistent regarding the effect of CPAP on mortality. Current studies are underpowered, with relatively short duration follow-up and methodological limitations.