Benefit of Adding Ezetimibe to Statin Therapy on Cardiovascular Outcomes and Safety in Patients With Versus Without Diabetes Mellitus: Results From IMPROVE-IT (Improved Reduction of Outcomes Vytorin Efficacy International Trial)
TIMI Study Group, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA (R.P.G., C.P.C., J.-G.P., E.A.B., E.B.).Duke Clinical Research Institute, Department of Medicine, Durham, NC (M.A.B., J.A.W.).Instituto do Coracao (InCor) Hospital das Clinicas, Faculdade de Medicina, Universidade de Sao Paulo, HCFMUSP, Brazil (J.C.N.).División Enfermedades Cardiovasculares, Centro Médico Clínica, Santiago, Chile (R.C.).Internal Cardiology Department, University Hospital Brno, Czech Republic (J.S.).
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Background:Ezetimibe, when added to simvastatin, reduces cardiovascular events after acute coronary syndrome. We explored outcomes stratified by diabetes mellitus (DM).Methods:In IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial), 18 144 patients after acute coronary syndrome with low-density lipoprotein cholesterol 50 to 125 mg/dL were randomized to 40 mg ezetimibe/simvastatin (E/S) or 40 mg placebo/simvastatin. The primary composite end point was cardiovascular death, major coronary events, and stroke. DM was a prespecified subgroup.Results:The 4933 (27%) patients with DM were more often older and female, had had a prior myocardial infarction and revascularization, and presented more frequently with non-ST segment elevation acute coronary syndrome compared with patients without DM (each P<0.001). The median admission low-density lipoprotein cholesterol was lower among patients with DM (89 versus 97 mg/dL, P<0.001). E/S achieved a significantly lower median time-weighted average low-density lipoprotein cholesterol compared with placebo/simvastatin, irrespective of DM (DM: 49 versus 67 mg/dL; no DM: 55 versus 71 mg/dL; both P<0.001). In patients with DM, E/S reduced the 7-year Kaplan–Meier primary end point event rate by 5.5% absolute (hazard ratio, 0.85; 95% confidence interval, 0.78-0.94); in patients without DM, the absolute difference was 0.7% (hazard ratio, 0.98; 95% confidence interval, 0.91–1.04; Pint=0.02). The largest relative reductions in patients with DM were in myocardial infarction (24%) and ischemic stroke (39%). No differences in safety outcomes by treatment were present regardless of DM. When stratified further by age, patients ≥75 years of age had a 20% relative reduction in the primary end point regardless of DM (Pint=0.91), whereas patients <75 years of age with DM had greater benefit than those without (Pint=0.011). When stratified by the TIMI (Thrombolysis in Myocardial Infarction) Risk Score for Secondary Prevention, all patients with DM demonstrated benefit with E/S regardless of risk. In contrast, among patients without DM, those with a high risk score experienced a significant (18%) relative reduction in the composite of cardiovascular death, myocardial infarction, and ischemic stroke with E/S compared with placebo/simvastatin, whereas patients without DM at low or moderate risk demonstrated no benefit with the addition of ezetimibe to simvastatin (Pint =0.034).Conclusions:In IMPROVE-IT, the benefit of adding ezetimibe to statin was enhanced in patients with DM and in high-risk patients without DM.Clinical Trial Registration:URL: https://www.clinicaltrials.gov. Unique identifier: NCT00202878.