Treatment of Obstructive Sleep Apnea Improves Cardiometabolic Function in Young Obese Women with Polycystic Ovary Syndrome

Context: Women with polycystic ovary syndrome (PCOS) are insulin resistant and have a high risk of early-onset diabetes and cardiovascular disease. Obstructive sleep apnea (OSA) has adverse cardiometabolic consequences and is highly prevalent in women with PCOS. We sought to determine whether continuous positive airway pressure (CPAP) treatment of OSA has beneficial effects on cardiometabolic function in PCOS. Methods: Laboratory polysomnography and cardiometabolic measurements including insulin sensitivity and secretion (iv glucose tolerance test); 24-h profiles of plasma catecholamines, cortisol, and leptin; and daytime profiles of blood pressure and cardiac autonomic activity (heart rate variability) were obtained at baseline and again after 8 wk of home CPAP treatment with daily usage monitoring. Results: CPAP treatment modestly improved insulin sensitivity after controlling for body mass index (P = 0.013). The change in insulin sensitivity correlated positively with CPAP use (adjusted P = 0.027) and negatively with body mass index (adjusted P = 0.003). Daytime and nighttime norepinephrine levels were decreased after CPAP (P = 0.002), and the reductions were greater with increased CPAP use (P = 0.03). Epinephrine, cortisol, and leptin levels were not changed significantly. Daytime diastolic blood pressure decreased by an average of 2.3 mm Hg after CPAP (P = 0.035). Cardiac sympathovagal balance was 44% lower (P = 0.007) after CPAP, reflecting a shift toward lower sympathetic activity. Conclusions: In young obese women with PCOS, successful treatment of OSA improves insulin sensitivity, decreases sympathetic output, and reduces diastolic blood pressure. The magnitude of these beneficial effects is modulated by the hours of CPAP use and the degree of obesity. (J Clin Endocrinol Metab 96: 365-374, 2011)