Effect of continuous positive airway pressure on carotid intima-media thickness in patients with obstructive sleep apnea: A meta-analysis.

OBJECTIVE: Obstructive sleep apnea (OSA) is associated with increased carotid intima-media thickness (IMT), an early marker of atherosclerosis. Continuous positive airway pressure (CPAP) is the first-line treatment for OSA. A meta-analysis was performed to determine whether CPAP therapy could decrease carotid IMT. METHODS: The PubMed, Embase, Web of Science, and Cochrane library were searched before March, 2017. Weighted mean difference (WMD) was calculated to estimate the treatment effects of pre and post-CPAP therapy. Seven studies were examined and the meta-analysis was performed using STATA 12.0. RESULTS: There was no change of carotid IMT before and after CPAP treatment in OSA patients (WMD = 0.052, 95% confidence interval (CI) = -0.002 to 0.105, z = 1.90, p = 0.057). Meanwhile, meta-analysis of the two RCTs showed that carotid IMT was not changed in CPAP group when compared with control group (WMD = 0.002 95% CI = -0.125 to 0.129, z = 0.03, p = 0.976). Subgroup analyses indicated that carotid IMT was significantly decreased after CPAP use in more severe OSA patients (AHI≥50) (WMD = 0.073, 95% CI = 0.022 to 0.124, z = 2.80, p = 0.005) and patients with therapeutic duration ≥6 months (WMD = 0.121, 95% CI = 0.019 to 0.223, z = 2.32, p = 0.021). CONCLUSIONS: CPAP had no impact on carotid IMT in OSA patients. However, carotid IMT was significantly decreased after CPAP treatment in more severe OSA patients and patients with longer CPAP usage.

Effect of positive airway pressure on glomerular filtration rate in patients with sleep-disordered breathing: a meta-analysis.

OBJECTIVE: Sleep-disordered breathing (SDB) has been suggested to be associated with chronic kidney disease (CKD). Positive airway pressure (PAP) is an effective treatment for SDB, but the impact of PAP therapy on glomerular filtration rate (GFR) in patients with SDB remains unclear. The present meta-analysis was performed to determine whether PAP therapy could increase GFR. DESIGN: A systematic search of PubMed, Embase, Web of Science, and Cochrane library was performed for literature published up to January 2016. Standardized mean difference (SMD) was calculated to estimate the treatment effects of pre- and post-PAP therapy. RESULTS: A total of eight studies with 240 patients were pooled into a meta-analysis. The meta-analysis showed that there was no change of GFR before and after PAP treatment in SDB patients (SMD = 0.010, 95 % confidence interval (CI) = -0.331 to 0.350, z = 0.06, p = 0.956), Subgroup analyses indicated that GFR was significantly increased after PAP treatment in elder patients (≥55 years) (SMD = -0.283, 95 % CI = -0.518 to -0.047, z = 2.35, p = 0.019) and patients with therapeutic duration ≥ 3 months (SMD = -0.276, 95 % CI = -0.522 to -0.031, z = 2.20, p = 0.027). CONCLUSION: The present meta-analysis suggested that PAP treatment had no impact on GFR in SDB patients. However, longer PAP usage for SDB patients significantly improved GFR. In elder SDB subjects, PAP was also associated with a statistically significant increase in GFR.