Determination of the Incidence of Cardiovascular Composite Events in Patients with Obstructive Sleep Apnea: A 3-year follow-up Study.

Background: The occurrence of obstructive sleep apnea (OSA) and its health-related issues, especially cardiovascular diseases (CVD), are increasing in developing countries. With a 3-year follow-up study, the present study aimed to determine the incidence of cardiovascular events in patients with OSA in an Iranian population.

Method: In this prospective cohort study, 415 adults (300 patients with OSA and 115 patients without OSA) with a history of snoring and/or witnessed apneas or other suspected sleep breathing disorders were consecutively enrolled and followed up for three successive years to evaluate the development of cardiovascular events including acute coronary syndrome, cerebrovascular accidents (including ischemic or hemorrhagic strokes or transient ischemic attacks), death due to cardiac causes and all-cause mortality.

Results: 415 patients were studied with a mean age of 56.2 ±15.7 years, 211 (50.8) of whom were male. Cardiovascular events developed in 15 participants (5%) of the OSA group, and 3 participants (2.6 %) of the OSA negative group. No significant differences were observed between the two groups in terms of the incidence of any of these events (P>0.05). Using multiple logistic regression model (with P<0.2 as the significance level), age, OSA, and history of CVD remained as significant predictors for the development of cardiac composite events (incidence of CVD, CVA, death due to cardiac causes, and all-cause mortality) with the odds ratios of (95% confidence interval) 1.03 (1.01, 1.06), 2.41 (1.02, 5.76), and 7.40 (2.91, 18.67), respectively.

Conclusions: The present study showed that OSA is associated with a more than twofold increased risk of cardiovascular events. Thus, obstructive sleep apnea should be considered an independent cardiovascular risk factor.