Natural course of untreated obstructive sleep apnea in adults with coronary artery disease in the RICCADSA cohort

RATIONALE: Recent randomized controlled trials failed to show cardiovascular benefits of treating obstructive sleep apnea (OSA) in intention-to-treat analyses, which has been a matter of debate since publication of the results. OBJECTIVES: To address whether untreated OSA persists after 1 year in adults with coronary artery disease (CAD) following revascularization and to explore whether major cardiovascular and cerebrovascular events (MACCEs) differ between the patients who persist vs improve in OSA severity. MEASUREMENTS: The study population included 119 CAD patients with moderate to severe OSA from the RICCADSA trial. All participants had an apnea-hypopnea index (AHI) ≥ 15/hour and were randomized to no continuous positive airway pressure (CPAP) therapy (n = 81) or were not using the device (n = 38). Patients without OSA (AHI < 5/h) at baseline (n = 85) were included as a control group. Home sleep apnea tests were performed at baseline and after 1 year. MAIN RESULTS: The median AHI decreased from 24.5 (19.4-36.0 events/h) to 15.1 (8.2-27.3 events/h) and oxygen desaturation index (4%) decreased from 14.8 (7.3-22.9 events/h) to 6.6 events/h (2.7-14.4 events/h) after 1 year (P < .001 for both). In all, 73 (61.3%) improved in OSA severity (59 had AHI 5-14.9 events/h and 14 had AHI < 5 events/h), whereas 46 (38.7%) had persistent OSA. The control group had a median AHI 4.4 (2.9-7.9 events/h) after 1 year. N-terminal-pro-B-type natriuretic peptide values decreased significantly in the overall cohort, with similar directional trends across OSA trajectory groups. The patients with improvement in OSA had significantly lower risk for MACCEs (hazard ratio [HR] = 0.25, 95% CI, 0.08-0.76; P = .015) compared to the patients with persistent OSA. CONCLUSIONS: Most of the CAD patients with moderate to severe OSA improve in OSA severity 1 year after revascularization, probably due to the improved cardiac function, and have a decreased risk for MACCEs compared to individuals with persistent OSA. Identifying patients with persistent OSA after revascularization may help target those most likely to benefit from focused intervention, particularly in settings where CPAP therapy is not initiated or is poorly tolerated.