Does treatment of nonsleepy OSA with CPAP therapy change CVD risk? A systematic review.

BACKGROUND: Nonsleepy obstructive sleep apnea (OSA) lacks daytime symptoms yet is associated with elevated cardiovascular risk. Continuous positive airway pressure (CPAP) is standard therapy, but cardiovascular benefits in nonsleepy OSA remain debated.

OBJECTIVE: To synthesize evidence on CPAP and cardiovascular outcomes in adults with nonsleepy OSA and quantify blood pressure (BP) effects where data permit.

METHODS: We performed a PRISMA-guided systematic review of Embase, PubMed, and Medline from inception through April 10, 2025 (PROSPERO: CRD420250480329). Eligible English-language studies included adults with nonsleepy OSA treated with CPAP and reported cardiovascular outcomes. Random-effects subgroup meta-analyses pooled systolic BP (SBP) and diastolic BP (DBP) from randomized controlled trials (RCTs) with extractable effect estimates.

RESULTS: Twelve studies (2006-2024) met inclusion criteria, including 11 RCTs (92%) and one post-hoc analysis (8%), with cohorts predominantly male and obese and comparators of placebo or standard care. All studies assessed BP; five reported marginal or no benefit and six suggested BP reductions, often adherence dependent. Cardiovascular event findings were inconsistent. Only four trials had extractable SBP data and three for DBP. Pooled estimates showed no significant SBP reduction (-0.42 mmHg; 95% CI -3.52 to 2.68; p = 0.69; I2 = 62%) but a significant DBP reduction (-2.33 mmHg; 95% CI -3.32 to -1.35; p = 0.01; I2 = 0%).

CONCLUSIONS: CPAP reduces DBP in pooled RCT data for nonsleepy OSA, while SBP and event-level effects vary. Standardized endpoints, longer follow-up, and comprehensive reporting are needed.