Effects of continuous positive airway pressure therapy on systemic inflammation in obstructive sleep apnea: A meta-analysis

Objectives: Our meta-analysis was performed to estimate the effect of continuous positive airway pressure (CPAP) therapy on systemic inflammation in patients with obstructive sleep apnea (OSA). Methods: A comprehensive literature search of PubMed and EMBASE was performed for literature published up to January 2013. Standardized mean difference (SMD) was calculated to estimate the treatment effects of pre- and post-CPAP therapy. Results: A total of 35 studies involving 1985 OSA patients were included in the meta-analysis. Each study investigated one or more inflammatory markers: 24 studies on C-reactive protein (CRP), 16 studies on IL-6, 3 studies on IL-8, and 12 studies on tumor necrosis factor alpha (TNF-alpha). The results showed that the SMD (95% confidence interval [CI]) for CRP, IL-6, IL-8, and TNF-alpha were 0.452 (95% CI, 0.252-0.651), 0.299 (95% CI, 0.001-0.596), 0.645 (95% CI, 0.362-0.929), and 0.478 (95% CI, 0.219-0.736) in pre- and post-CPAP therapy, respectively. The subgroup analyses seemed to support better benefits with therapy duration of >= 3 months and more adequate compliance (>= 4 h/night). Conclusions: CPAP therapy could partially suppress systemic inflammation in OSA patients, and substantial differences were present among the various inflammatory markers. (C) 2013 Elsevier B. V. All rights reserved.