Effects of continuous positive airway pressure on plasma fibrinogen levels in obstructive sleep apnea patients: a systemic review and meta-analysis.

OBJECTIVE Fibrinogen has been implicated to play a role in the pathophysiology of obstructive sleep apnea (OSA). Many studies have evaluated the effect of continuous positive airway pressure (CPAP) on plasma fibrinogen levels in OSA patients. However, results from different reports were not consistent. To assess the effect of CPAP treatment on plasma fibrinogen levels of patients with OSA, a meta-analysis was performed. METHODS A systematic search of Pubmed, Embase, Cochrane, Wanfang Database and Chinese National Knowledge Infrastructure was performed. Data were extracted, and then weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated using a random-effects model. RESULTS Twenty-two studies involving 859 patients were included in this meta-analysis. Combined data showed that plasma fibrinogen concentrations decreased after CPAP therapy (WMD = -0.38 g/l, 95% CI [-0.54 to -0.22 g/l], P<0.001). In the subgroup analyses by therapy duration, plasma fibrinogen concentrations declined significantly in the long-term (≥1 month) CPAP therapy subgroup (WMD = -0.33 g/l, 95% CI [-0.49 to -0.16 g/l], P<0.001) but not in the short-term (<1 month) CPAP therapy subgroup (WMD = -0.84 g/l, 95% CI [-1.70 to 0.03 g/l], P=0.058). Moreover, in patients with long-term CPAP therapy duration, plasma fibrinogen levels decreased with good CPAP compliance (≥4 h/night) (WMD = -0.37 g/l, 95% CI [-0.55 to -0.19 g/l], P<0.001) but not with poor CPAP compliance (<4 h/night) (WMD = 0.12 g/l, 95% CI [-0.09 to 0.33 g/l], P=0.247). CONCLUSION Long-term CPAP treatment with good compliance can reduce the plasma fibrinogen levels in patients with OSA.