High cardiovascular risk profile in patients with sleep apnea

Abstract

Objectives/hypothesis: Sleep apnea is associated with hypertension and diabetes, putting these patients at high risk for developing cardiovascular disease. The goal of this study was to identify the individual cardiovascular risk profile and to detect premature and undiagnosed disease in patients with various degrees of sleep apnea.

Study design: Cross-sectional.

Methods: Over a 6-month period, we consecutively characterized all patients referred to our sleep laboratory for an initial evaluation of sleep apnea. Clinical history; blood tests with oral glucose tolerance test, when appropriate; test for microalbuminuria; and an electrocardiogram (ECG) were performed. The Framingham general cardiovascular risk score was assessed in each patient.

Results: A total of 255 patients were evaluated. Of those, 190 (75%) were diagnosed with sleep apnea. Patients with sleep apnea had a significantly higher Framingham risk score than patients without sleep apnea. Adjusted for age and gender, severe sleep apnea was associated with a 60% increased cardiovascular risk compared with not having sleep apnea. In sleep apnea patients without previously diagnosed hypertension, an additional 45% had significant elevated blood pressure. Among sleep apnea patients without known diabetes, we tested 48% with a pathological glucose disposal. Twenty percent of sleep apnea patients without known heart disease had significant ECG changes.

Conclusions: High Framingham score, undiagnosed hypertension, and pathological glucose disposal were highly prevalent in patients with sleep apnea. Appropriate screening routines are important to detect cardiovascular risk factors in patients with sleep apnea.

Keywords: ECG; Sleep apnea; cardiovascular risk; diabetes; hypertension.