Cardiovascular risk factors in patients with obstructive sleep apnoea syndrome

Cardiovascular disorders are common in patients with obstructive sleep apno ea syndrome (OSAS) but there is debate as to whether OSAS is an independent risk factor for their development, since OSAS may be associated with other disorders and risk factors that predispose to cardiovascular disease. In an effort to quantify the risk of OSAS patients for cardiovascular disea se arising from these other factors, the authors assessed the future risk f or cardiovascular disease among a group of 114 consecutive patients with es tablished OSAS prior to nasal continuous positive airway pressure therapy, using an established method of risk prediction employed in the Framingham s tudies. Patients were 100 males, aged (mean+/-SD) 52+/-9.0 yrs, and 14 females, age d 51+/-10.4 yrs, with an apnoea/hypopnoea index of 45+/-22.h(-1). Based on either a prior diagnosis, or a mean of three resting blood pressure recordi ngs >140 mmHg systolic and/or 90 diastolic, 68% of patients were hypertensi ve. Only 18% were current smokers, while 16% had either diabetes mellitus o r impaired glucose tolerance, and 63% had elevated fasting cholesterol and/ or triglyceride levels. The estimated 10-yr risk of a coronary heart diseas e (CHD) event in males was (mean+/-SEM) 13.9+/-0.9%, 95% confidence interva l (95% CI) 12.1-16.0, and for a stroke was 12.3+/-1.4%; 95% CI 9.4-15.1, wi th a combined 10 yr risk for stroke and CHD events of 32.9+/-2.7%; 95% CI 2 7.8-38.5 in males aged >53 yrs. These findings indicate that obstructive sleep apnoea syndrome patients are at high risk of future cardiovascular disease from factors other than obst ructive sleep apnoea syndrome, and may help explain the difficulties in ide ntifying a potential independent risk from obstructive sleep apnoea syndrom e.