SAN FRANCISCO — Obstructive sleep apnea is tied to a 30% increased risk of myocardial infarction or death even after adjustment for many cofactors, Dr. Neomi A. Shah said at the International Conference of the American Thoracic Society.
Moreover, the greater the severity of obstructive sleep apnea (OSA), the greater the risk of MI or death, said Dr. Shah of Yale University, New Haven, Conn.
The observational cohort study of 1,640 patients referred for polysomnography compared the 844 patients who didn't qualify for an OSA diagnosis with the 796 who did. The patients were followed for 5 years. The mean apnea-hypopnea index (AHI) of those with OSA was 47.8, compared with 5.1 in the controls.
After adjustment for cardiovascular risk factors and other confounders, OSA was associated with a 40% increased risk of myocardial infarction or death. There was also a dose-response relationship between OSA severity as judged by AHI and the adjusted risk of myocardial infarction or death.
Compared with patients in the lowest quartile (AHA 0–4), those in the highest quartile (AHA > 30) had a 90% increased risk of myocardial infarction or death. Those in the second quartile (AHA 5–14) had a 20% greater risk, and those in the third quartile (AHA 15–30), a 50% greater risk, a statistically significant trend.