Concomitant Sleep Apnea and Diabetes Mellitus Are Independently Associated with Cardiovascular Events and Hospitalization for Heart Failure after Coronary Artery Bypass Grafting

BackgroundSleep apnea is a prevalent condition and an indicator of a poor outcome after coronary artery bypass grafting (CABG). Previous studies have not explored the relative and combined effects of sleep apnea with diabetes mellitus (DM) on cardiovascular outcomes in patients undergoing CABG.MethodsIn this secondary analysis of data from the SABOT study, 1007 patients were reclassified into four groups based on their sleep apnea and DM statuses, yielding 295, 218, 278, and 216 patients in the sleep apnea (+) DM (+), sleep apnea (+) DM (−), sleep apnea (−) DM (+), and sleep apnea (−) DM (−) groups, respectively. The primary end point was a major adverse cardiac and cerebrovascular event (MACCE), which encompasses cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke, and unplanned revascularization. Hospitalization for heart failure was a key secondary end point.ResultsAfter a mean follow-up period of 2.1 years, the crude incidence of MACCEs was 18% in the sleep apnea (+) DM (+), 11% in the sleep apnea (+) DM (−), 13% in the sleep apnea (−) DM (+), and 5% in the sleep apnea (−) DM (−) groups. Using sleep apnea (−) DM (−) as the reference group, a Cox regression analysis indicated that sleep apnea (+) and DM (+) independently predicted MACCEs (adjusted hazard ratio, 3.2; 95% confidence interval, 1.7–6.2; p = 0.005) and hospitalization for heart failure (adjusted hazard ratio, 12.6; 95% confidence interval, 3.0–52.3; p < 0.001) after adjusting for age, sex, body mass index, left ventricular ejection fraction, hypertension, chronic kidney disease, and excessive daytime sleepiness.ConclusionSleep apnea and DM have independent negative effects on the prognosis of patients undergoing non-emergent CABG.Clinical Trial RegistrationClinicalTrials.gov identification no. NCT02701504