Discharge β-Blocker Use and Race after Coronary Artery Bypass Grafting

INTRODUCTION The use of discharge β-blockers after cardiac surgery is associated with a long-term mortality benefit. β-Blockers have been suggested to be less effective in black cardiovascular patients compared with whites. To date, racial differences in the long-term survival of coronary artery bypass grafting (CABG) patients who receive β-blockers at discharge have not been examined. METHODS A retrospective cohort study was conducted on patients undergoing CABG between 2002 and 2011. Long-term survival was compared in patients who were and who were not discharged with β-blockers. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. P-for-interaction between race and discharge β-blocker use was computed using a likelihood ratio test. RESULTS A total of 853 (88%) black (n = 970) and 3,038 (88%) white (n = 3,460) patients had a history of β-blocker use at discharge (N = 4,430). Black patients who received β-blockers survived longer than those not receiving β-blockers and the survival advantage was comparable with white patients (black, adjusted HR = 0.33, 95% CI = 0.23-0.46; white, adjusted HR = 0.48, 95% CI = 0.39-0.58; p-for-interaction = 0.74). Among patients discharged on β-blockers, we did not observe a long-term survival advantage for white compared with black patients (HR = 1.2, 95% CI = 0.95-1.5). CONCLUSION β-Blocker use at discharge was associated with a survival advantage among black patients after CABG and a similar association was observed in white patients.