Effect of continuous positive airway pressure on homocysteine levels in patients with obstructive sleep apnea: a meta-analysis

Continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea hypopnea syndrome (OSAHS), but previous studies assessing the effect of CPAP on homocysteine (HCY) in patients with OSAHS yielded conflicting results. In this study, we conducted a meta-analysis to determine whether CPAP therapy could reduce plasma HCY levels. Searches of PUBMED, SCI, and Elsevier databases were completed. Studies of adult patients with OSAHS who reported HCY levels pre- and post-CPAP treatment were collected by two independent reviewers. RevMan (version 5.2) and STATA (version 12.0) were used to perform data synthesis. A total of 6 studies involving 206 participants were included. Meta-analysis showed that the total weighted mean difference (WMD) for HCY levels was -0.62 units (95 % confidence interval (CI) -1.21 to -0.04, P < 0.05) post- and pre-CPAP therapy. Subgroup analysis showed that HCY was decreased nonsignificantly within 3 months after the therapy (WMD, -0.07, 95 % CI -0.88 to 0.74, P > 0.05), but it was significantly reduced after 3 months therapy (WMD, -1.22, 95 % CI -2.07 to -0.38,P < 0.05). This meta-analysis suggests that HCY levels were significantly reduced by CPAP therapy in patients with OSAHS and the HCY levels may be clinically recognized as a valuable indicator for OSAHS treatment, but the clinical significance of this finding as it relates to cardiovascular risk reduction in OSAHS patients warrants further study.