Predictors and Outcomes of Routine Versus Optimal Medical Therapy in Stable Coronary Heart Disease

Abstract

Although randomized studies have shown optimal medical therapy (OMT) to be as efficacious as revascularization in stable coronary heart disease (CHD), the application of OMT in routine practice is suboptimal. We sought to understand the predictors of receiving OMT in stable CHD and its impact on clinical outcomes. All patients with stable CHD based on coronary angiography from October 2008 to September 2011 were identified in Ontario, Canada. OMT was defined as concurrent use of β blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, and statin. Aspirin use was not part of the OMT definition because of database limitations. Multivariable hierarchical logistic models identified predictors of OMT in the 12months after angiography. Cox proportional hazard models with time-varying covariates for OMT and revascularization status examined differences in death and nonfatal myocardial infarction (MI). In these models, patients transitioned among 4 mutually exclusive treatment groups: no OMT and no revascularization, no OMT and revascularization, OMT and no revascularization, OMT and revascularization. Our cohort had 20,663 patients. Over a mean period of 2.5years, 8.7% had died. Only 61% received OMT within 12months. The strongest predictor of receiving OMT at 12months was OMT before the angiogram (odds ratio 14.40, 95% confidence interval [CI] 13.17 to 15.75, p <0.001). Relative to no OMT and nonrevascularized patients, patients on OMT and revascularized had the greatest reduction in mortality (hazard ratio 0.52, 95% CI 0.45 to 0.60, p <0.001) and nonfatal MI (hazard ratio 0.74, 95% CI 0.64 to 0.84, p<0.001). In conclusion, our study highlights the low rate of OMT in stable CHD. Patients who received both OMT and revascularization achieved the greatest reduction in mortality and nonfatal MI.