Purpose: Continuous positive airway pressure (CPAP) therapy may decrease the risk of mortality and cardiovascular events in patients with obstructive sleep apnea. However, these benefits are not completely clear.
Methods: We undertook a meta-analysis of randomized clinical trials identified in systematic searches of MEDLINE, EMBASE, and the Cochrane Database.
Results: Eighteen studies (4146 patients) were included. Overall, CPAP therapy did not significantly decrease the risk of cardiovascular events compared with the control group (odds ratio (OR), 0.84; 95 % confidence intervals (CI), 0.62-1.13; p = 0.25; I (2) = 0 %). CPAP was associated with a nonsignificant trend of lower rate of death and stroke (for death: OR, 0.85; 95 % CI, 0.35-2.06; p = 0.72; I (2) = 0.0 %; for stroke: OR, 0.56; 95 % CI, 0.18-1.73; p = 0.32; I (2) = 12.0 %), a significantly lower Epworth sleepiness score (ESS) (mean difference (MD), -1.78; 95 % CI, -2.31 to -1.24; p < 0.00001; I (2) = 76 %), and a significantly lower 24 h systolic and diastolic blood pressure (BP) (for 24 h systolic BP: MD, -2.03 mmHg; 95 % CI, -3.64 to -0.42; p = 0.01; I (2) = 0 %; for diastolic BP: MD, -1.79 mmHg; 95 % CI, -2.89 to -0.68; p = 0.001; I (2) = 0 %). Daytime systolic BP and body mass index were comparable between the CPAP and control groups. Subgroup analysis did not show any significant difference between short- and mediate-to-long-term follow-up groups with regard to cardiovascular events, death, and stroke.
Conclusions: CPAP therapy was associated with a trend of decreased risk of cardiovascular events. Furthermore, ESS and BP were significantly lower in the CPAP group. Larger randomized studies are needed to confirm these findings.
Keywords: Cardiovascular events; Continuous positive airway pressure; Meta-analysis; Mortality; Obstructive sleep apnea; Sleepiness.