Effect of continuous positive airway pressure on lipid profile in patients with obstructive sleep apnea syndrome: A meta-analysis of randomized controlled trials

Background: Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for development of dyslipidemia. Continuous positive airway pressure (CPAP) is the first-line treatment for OSAS. However, it is unclear whether CPAP improves lipid metabolism. Objectives: To review the effect of CPAP on lipid profile of patients with OSAS. Methods: We searched PubMed, Embase, and the Cochrane Library to identify eligible articles published prior to October 30, 2013. Six randomized controlled trials (RCTs) were subjected to meta-analysis using Comprehensive Meta-Analysis software. Results: Six RCTs meeting the inclusion criteria were enrolled. The total numbers of measurements of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol, in CPAP intervention patients and sham/control groups, were 370 and 371, 330 and 328, 276 and 274, and 269 and 266 respectively. The pooled estimate of the difference in the mean TC level between the CPAP and sham CPAP/control groups was significantly different (-0.15 [95% confidence interval, -0.27 to -0.03]; p 0.01). Subgroup analysis revealed that OSAS patients of younger age, who were more obese, and who had been treated via CPAP for a longer duration, showed a significant decrease in TC levels (the differences in the means were -0.27, -0.24, and -0.20; and the p values 0.001, 0.01, and 0.04, respectively). Conclusion: We confirmed that CPAP decreases the TC level, especially in OSAS patients who are younger, more obese, and who use CPAP for a longer period. CPAP did not alter TG, LDL, or HDL levels, suggesting that CPAP may have no clinically important effect on lipid metabolism. (C) 2014 The Authors. Published by Elsevier Ireland Ltd.