Effects of continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea in arterial stiffness: a meta-analysis

Obstructive sleep apnea (OSA) is associated with increased arterial stiffness, a cumulative indicator of arterial health. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA. We conducted a meta-analysis of the available literature investigating the effect of CPAP on arterial stiffness in patients with OSA. Fifteen articles (n = 615 patients) assessing indices of arterial stiffness were identified. Five different meta-analyses were performed assessing: a) all indices of arterial stiffness, b) augmentation index (AIx), c) all pulse wave velocities (PWV), d) brachial-ankle PWV and e) carotid-femoral PWV. Pooled standardized mean differences (SMDs) and weighted mean differences (WMDs) were appropriately calculated through fixed or random effects models after assessing between-study heterogeneity. A significant improvement of all indices of arterial stiffness was observed after CPAP treatment (SMD = -0.74; 95%CI: -1.08 to -0.41). AIx and PWVs were also significantly improved (WMD = -4.86; 95%CI: -7.31 to -2.41 and WMD = -0.87; 95%CI: -0.98 to -0.77, respectively), as well as brachial-ankle PWV and carotid-femoral PWV (WMD = -0.86; 95%CI: -0.97 to -0.75 and WMD = -1.21; 95%CI:-1.92 to -0.50, respectively). Neither the proportion of compliant patients nor the duration of CPAP use altered the effect of arterial stiffness reduction after CPAP treatment. In conclusion, our meta-analyses showed significant improvements in all indices of arterial stiffness after CPAP treatment in patients with OSA. As clinical use of arterial stiffness is growing in popularity, the efficacy of this useful tool in assessing cardiovascular risk reduction among patients with OSA treated with CPAP needs to be further explored.