NEW YORK (Reuters Health) – Obstructive sleep apnea treatment is associated with a marked cardiovascular risk reduction, according to findings published in the December 15 issue of the American Journal of Respiratory and Critical Care Medicine.

"Obstructive sleep apnea (OSA) is linked to increased cardiovascular risk, but the impact of mild forms of OSA and their treatment on cardiovascular outcomes remains controversial," Dr. Nikolaus J. Buchner, of Ruhr University Bochum, Herne, Germany, and colleagues write.

In the present study, the researchers prospectively examined cardiovascular outcomes in treated versus untreated patients with all degrees of OSA. A total of 449 consecutive sleep laboratory patients were included in the study. Study endpoints included nonfatal (myocardial infarction, stroke, and acute coronary syndromes requiring revascularization procedures) and fatal (death from myocardial infarction or stroke) cardiovascular events.

Of the 449 patients enrolled in the study, 364 received OSA treatment (CPAP in 296, bilevel positive airway pressure in 48, and intraoral protrusion devices in 20), and 85 refused treatment. The patients were followed for a median of 72.0 months. The mean apnea-hypopnea index before treatment was 30.9/h in treated subjects and 15.3/h in untreated subjects. There were no differences between the groups in cardiovascular comorbidities or risk factors.

The authors report that 76 events occurred during the observation period in the whole study group. Among patients with mild to moderate OSA, there were more events in untreated patients than in treated patients (25.3% versus 14.4%, respectively; p = 0.024).

OSA treatment was an independent predictor for events after adjustment for age, gender, BMI, cardiovascular risk factors, cardiovascular disease, COPD, and malignant disorders. Treated patients had a significantly lower risk of events compared to untreated patients. OSA treatment was associated with 64% reduction in risk for the whole study group and for those with mild to moderate OSA.

"OSA treatment should be considered for primary and secondary cardiovascular prevention, even in milder OSA," the authors conclude.

Am J Respir Crit Care Med 2007;176:1274-1280.

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