Case-control study with a 6-year follow-up of the case cohort. 192 acute MI patients and 96 matched control subjects without coronary artery disease (CAD) (ratio 2:1). After overnight polysomnography, CPAP was recommended if apnea-hypopnea index (AHI) ¡Ý 5, and a mean daily use > 3.5 h/day was considered necessary to maintain the treatment. Lipids, fasting glucose, blood pressure, spirometry, comorbidity and current treatment were also registered. End-points were recurrent MI or need of revascularization.
OSA was an independent predictor of MI, with odds ratio 4.9 (95 % confidence interval [CI] 2.9-8.3, p = 0.017). 63 MI patients without OSA, 52 untreated patients with OSA and 71 OSA patients treated with CPAP were included in the follow-up study. After adjustment for confounding factors, treated OSA patients had a lower risk of recurrent MI (adjusted hazard ratio 0.16 [95 % CI 0.03-0.76, p = 0.021]) and revascularization (adjusted hazard ratio 0.15 [95 % CI 0.03-0.79, p = 0.025]) than untreated OSA patients, and similar to non-OSA patients.
Mild-severe OSA is an independent risk factor for MI. Risk of recurrent MI and revascularization was lower in OSA patients who tolerated CPAP.