Continuous positive airway pressure and cardiovascular outcomes in obstructive sleep apnoea patients: a systematic review and meta-analysis of randomized controlled trials

Background: Continuous positive airway pressure (CPAP) has been utilized to reduce blood pressure in obstructive sleep apnea (OSA) patients, but few studies are available in terms of mortality data and other cardiovascular outcomes. Methods: This study systematically searched PubMed, Embase, and Cochrane Library databases for studies investigating the effects of CPAP on OSA patients. Basic characteristics and outcomes were extracted. A random effects model was used to pool the overall size. Q and I-2 statistics were employed to quantify between-group heterogeneity. Egger's and Begg's tests were employed to identify small-study effects. Results: Of 590 primary records, 9 randomized controlled trials, including 5,923 patients, were finally included in the meta-analysis. CPAP was not associated with all-cause mortality (relative risk [95% confidence interval]: 0.92 [0.65-1.30], I-2 = 0.0%) or cardiovascular mortality (0.70 [0.27-1.80], I-2 = 36.3%) in OSA population. Incidence of myocardial infarction (0.95 [0.53-1.70], I-2 = 25.8%) or strokes (0.91 [0.68-1.24], I-2 = 0.0%) was not significantly different between the CPAP group and non-CPAP group. Neither Egger's nor Begg's tests indicated any small-study effects. Conclusion: CPAP was not significantly associated with all-cause mortality, cardiovascular mortality, or occurrence of myocardial infarction and strokes in the OSA population.