Effects of continuous positive airway pressure on cardiovascular risk profile in patients with severe obstructive sleep apnea and metabolic syndrome.

BACKGROUND: The increased risk of atherosclerotic morbidity and mortality in patients with obstructive sleep apnea (OSA) has been linked to arterial hypertension, insulin resistance, systemic inflammation, and oxidative stress. We aimed to determine the effects of 8 weeks of therapy with continuous positive airway pressure (CPAP) on glucose and lipid profile, systemic inflammation, oxidative stress, and global cardiovascular disease (CVD) risk in patients with severe OSA and metabolic syndrome.
METHODS: In 32 patients, serum cholesterol, triglycerides, high-density lipoprotein cholesterol, fibrinogen, apolipoprotein A-I, apolipoprotein B (ApoB), high-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor (TNF)-alpha, leptin, malondialdehyde (MDA), and erythrocytic glutathione peroxidase (GPx) activity were measured at baseline and after 8 weeks of CPAP. The insulin resistance index (homeostasis model assessment [HOMA-IR]) was based on the homeostasis model assessment method, the CVD risk was calculated using the multivariable risk factor algorithm.
RESULTS: In patients who used CPAP for > or = 4 h/night (n = 16), CPAP therapy reduced systolic BP and diastolic BP (p = 0.001 and p = 0.006, respectively), total cholesterol (p = 0.002), ApoB (p = 0.009), HOMA-IR (p = 0.031), MDA (p = 0.004), and TNF-alpha (p = 0.037), and increased erythrocytic GPx activity (p = 0.015), in association with reductions in the global CVD risk (from 18.8 +/- 9.8 to 13.9 +/- 9.7%, p = 0.001). No significant changes were seen in patients who used CPAP for < 4 h/night. Mask leak was the strongest predictor of compliance with CPAP therapy.
CONCLUSIONS: In patients with severe OSA and metabolic syndrome, good compliance to CPAP may improve insulin sensitivity, reduce systemic inflammation and oxidative stress, and reduce the global CVD risk.