Cardiovascular risk factors in patients with obstructive sleep apnoea syndrome

Abstract

Cardiovascular disorders are common in patients with obstructive sleep apnoea 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 disease arising from these other factors, the authors assessed the future risk for cardiovascular disease among a group of 114 consecutive patients with established OSAS prior to nasal continuous positive airway pressure therapy, using an established method of risk prediction employed in the Framingham studies.Patients were 100 males, aged (meanSD) 529.0 yrs, and 14 females, aged 5110.4 yrs, with an apnoea/hypopnoea index of 4522 . h -1 . Based on either a prior diagnosis, or a mean of three resting blood pressure recordings >140 mmHg systolic and/or 90 diastolic, 68% of patients were hypertensive. Only 18% were current smokers, while 16% had either diabetes mellitus or impaired glucose tolerance, and 63% had elevated fasting cholesterol and/or triglyceride levels. The estimated 10-yr risk of a coronary heart disease (CHD) event in males was (meanSEM) 13.90.9%, 95% confidence interval (95% CI) 12.1±16.0, and for a stroke was 12.31.4%; 95% CI 9.4± 15.1, with a combined 10 yr risk for stroke and CHD events of 32.92.7%; 95% CI 27.8±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 obstructive sleep apnoea syndrome, and may help explain the difficulties in identifying a potential independent risk from obstructive sleep apnoea syndrome.

All-cause mortality in males with sleep apnoea syndrome: declining mortality rates with age

“…But this did not provide an adequate control for the possible differences in medical history between patients with different severities of sleep apnoea. It is well-documented that by the time of diagnosis, sleep apnoea patients display a high rate of cardiovascular morbidity that significantly increases with apnoea severity [7,20]. Furthermore, several follow-up studies reported an increased incidence of cardiovascular morbidity in middle-age sleep apnoea patients who were free of such morbidity at the diagnosis [21][22][23], even without a change in apnoea severity [24].…”

“…Patients with severe sleep apnoea have additional risk factors, which could be expected to greatly exacerbate their risk of mortality. By the time of their diagnosis a substantial proportion suffer from cardiovascular morbidity [19][20][21]. An independent association between cardiovascular morbidity and breathing disorders in sleep was reported even for patients with a very mild form of disordered breathing in sleep, that falls within the normal range of 1-10 respiratory events per hour of sleep [5,8,38].…”

Early left ventricular functional alterations in patients with obstructive sleep apnea syndrome

“…Some studies have described that OSAS is not an independent risk factor in the development of CV disorders [11][12][13]. However, other studies have stated that the rate of mortality is significantly higher in non-treated patients with AHI values over 20 [14], and the incidence of CVD in non-treated patients with moderate-severe OSAS is markedly increased compared to normal individuals or treated patients [15].…”

Sleep Apnea, the Risk of Developing Heart Failure, and Potential Benefits of Continuous Positive Airway Pressure (CPAP) Therapy

“…Sleep apnea (SA) is associated with increased risk of cardiovascular events, worsening of heart failure (HF), metabolic disturbances, and overall a reduced quality of life 1, 2, 3, 4. One study even found an increased risk of incident HF among men with obstructive sleep apnea (OSA) 5.…”