Relationship of metabolic syndrome and obstructive sleep apnea

Study Objectives: Obstructive sleep apnea (OSA) and metabolic syndrome represent significant risk factors for the development of cardiovascular disease. The purpose of this study was to see how frequently metabolic syndrome occurred in patients with OSA and whether the presence of metabolic syndrome was correlated with age, sex, or severity of OSA. Methods: We examined the records of 250 consecutive patients referred to our Sleep Disorders Center to have polysomnography for the evaluation of OSA and extracted clinical data from the patients' medical records. We compared the proportion of patients with OSA and metabolic syndrome, hypertension, diabetes, or dyslipidemia to the group without OSA. We also did subgroup analysis by age and sex. Results: A total of 228 patients were included in the study. Of 146 patients with OSA, 88 (60%) had metabolic syndrome, whereas 33 of 82 patients (40%) without significant OSA had metabolic syndrome (p = .004). The proportion with hypertension was significantly higher in the OSA group (77% vs 51%; p = .001). The proportion of patients with hyperglycemia and dyslipidemia was not significantly different between the 2 groups. In men older than age 50 years, there was a significantly higher than expected proportion of OSA patients with metabolic syndrome and in the proportion with hypertension but not with a diagnosis of diabetes or dyslipidemia. In women (both older and younger than age 50), and in men younger than age 50, there was not an independent relationship between metabolic syndrome and OSA. Conclusions: Patients with OSA have a high prevalence of metabolic syndrome. The prevalence of metabolic syndrome and hypertension was significantly greater in the OSA group. No significant differences were noted between the 2 groups in the proportion of patients with diabetes and dyslipidemia.