Projected Outcomes of Optimized Statin and Ezetimibe Therapy in US Military Veterans with Coronary Artery Disease

IMPORTANCE: Many patients with coronary artery disease (CAD) do not achieve the guideline-directed goals for low-density lipoprotein cholesterol (LDL-C) levels. OBJECTIVE: To estimate reductions in the rates of adverse events associated with CAD in a large US military veteran population that may be achieved through use of optimized statin therapy alone or with ezetimibe compared with the prevailing lipid-lowering therapy (LLT). DESIGN, SETTING, AND PARTICIPANTS: In this observational cohort study, US military veterans with CAD were identified by coronary angiography between June 2015 and September 2020 across 82 US Department of Veterans Affairs health care facilities. EXPOSURES: The exposures were observed LLT, LLT with an optimized statin regimen, and LLT with optimized statin and ezetimibe. MAIN OUTCOMES AND MEASURES: Observed rates of death, myocardial infarction, stroke, and coronary revascularization, and potential reductions in those outcomes with optimized LLT based on expected further reductions in LDL-C levels and application of formulas from The Cholesterol Treatment Trialists’ Collaboration. RESULTS: The analysis cohort comprised 111 954 veterans (mean [SD] age, 68.4 [8.8] years; 109 390 men [97.7%]; 91 589 White patients [81.8%]; 17 592 Black patients [15.7%]). The median (IQR) observation period for this study was 3.4 (2.1-4.0) years. At the time of index angiography, 66 877 patients (59.7%) were treated with statin therapy, and 623 patients (0.6%) were treated with ezetimibe. At 6 months, the number of patients with statin prescriptions increased to 74 400 (68.7%), but the number of patients with high-intensity statin prescriptions was only 57 297 (52.9%). At 6 months, ezetimibe use remained low (n = 1168 [1.1%]), and LDL-C levels were 70 mg/dL or more in 56 405 patients (52.1%). At 4 years, observed incidences of death, myocardial infarction, stroke, and coronary revascularization were 21.6% (95% CI, 21.3%-21.8%), 5.0% (95% CI, 4.9%-5.2%), 2.2% (95% CI, 2.1%-2.3%), and 15.4% (95% CI, 15.2%-15.7%), respectively. With optimized statin treatment, projected absolute reductions in these incidences were 1.3% (95% CI, 0.9%-1.7%), 0.8% (95% CI, 0.7%-1.0%), 0.2% (95% CI, 0.1%-0.3%), and 2.3% (95% CI, 2.0%-2.7%), respectively. With optimized statin and ezetimibe treatment, projected absolute reductions were 1.8% (95% CI, 1.2%-2.4%), 1.1% (95% CI, 0.9%-1.3%), 0.3% (95% CI, 0.2%-0.4%), and 3.1% (95% CI, 2.6%-3.6%), respectively. CONCLUSIONS AND RELEVANCE: In this cohort study of veterans with CAD, suboptimal LLT was prevalent in the clinical setting. Optimization of statin therapy was projected to produce clinically relevant reductions in the risks of death and cardiovascular events. Despite a lesser lipid-lowering efficacy of ezetimibe, its widespread use on a population level in conjunction with optimized statin therapy may be associated with further meaningful reductions in cardiovascular risk.