Study Shows Importance of Adherence to Medical Therapy on Long-Term Outcomes Regardless of Revascularization Strategy

October 24, 2016—An evaluation of the impact of adherence to medical therapy on comparative outcomes of coronary artery bypass graft (CABG) versus percutaneous coronary intervention (PCI) was published by Paul Kurlansky, MD, et al in Circulation (2016;134:1238–1246).

The investigators found that regardless of coronary revascularization strategy, medication adherence has a dramatic effect on long-term outcome. They stated that among comparable patients who adhere to optimal medical therapy, outcomes of PCI and CABG may not differ; however, among nonadherent patients, CABG affords better major adverse cardiac event–free survival. Therefore, patient compliance with medical therapy may inform clinical decision-making and should be incorporated into all future comparative studies of coronary revascularization strategies, concluded the investigators.

For the study, the investigators followed all non–ST-segment–elevation myocardial infarction patients undergoing coronary revascularization in an eight-hospital network for up to 8 years to determine medication history and major adverse cardiac events (MACE; defined as all-cause mortality, nonfatal myocardial infarction, and reintervention). 

The investigators checked all mortalities against the Social Security Death Index. The survival curves were developed using Kaplan-Meier methods and hazard ratios were obtained using the Cox proportional hazard model. Propensity score matching was used to account for differences in patient selection. 

As summarized in Circulation, among the 973 CABG and 2,255 PCI patients, Kaplan-Meier MACE–free survival curves demonstrated a significant benefit for antiplatelet, lipid-lowering, and β-blocker therapy in both the CABG and PCI groups (P = .001 for all three medications). 

Cox regression identified compliance with optimal medical therapy as a more powerful predictor of MACE–free survival than choice of therapy (hazard ratio for noncompliance, 2.79; 95% confidence limits, 2.19–3.54; P < .001; hazard ratio for PCI vs CABG, 1.68; 95% confidence limits, 138–2.04; P < .001). In propensity-matched patients, CABG outcomes were superior to PCI outcomes in patients nonadherent to optimal medical therapy (P = .001) but were not different in patients adherent to optimal medical therapy (P = .574), reported the investigators in Circulation.