Lipid-lowering drug use and cardiovascular events after myocardial infarction

Abstract

BACKGROUND: The benefits of lipid-lowering drug treatment for the secondary prevention of coronary heart disease have been well established by randomized, controlled trials. Nonetheless, the risk of events has not been compared directly for inhibitors of hydroxymethylglutaryl coenzyme A reductase (statins) and non-statin lipid-lowering drugs. Further, it remains uncertain whether patients in usual practice who are treated with lipid-lowering drugs after myocardial infarction (MI) gain a similar benefit with regard to the risk of cardiovascular events compared with patients in randomized, controlled trials. OBJECTIVE: To assess the association between lipid-lowering drug therapies in usual clinical practice and the risk of cardiovascular events in patients with a first MI who were discharged alive from the hospital. METHODS: An inception-cohort study was performed among 1956 enrollees of Group Health Cooperative who sustained an incident MI between July 1986 and December 1996 and survived for at least 6 months after hospitalization. Subjects with untreated low-density-lipoprotein cholesterol concentrations > 130 mg/dL or untreated total cholesterol concentrations >200 mg/dL were included. The median duration of follow-up after the first MI was 3.3 years. Medical record review was used to collect information on cardiovascular risk factors. Computerized pharmacy records were used to assess antihyperlipidemic drug use during the first 6 months after hospitalization. RESULTS: Compared with 1263 subjects who did not receive lipid-lowering drug treatment, 373 subjects who received statins had a lower risk of recurrent coronary events (relative risk [RR] 0.59; 95% CI 0.39 to 0.89), stroke (RR 0.82; 95% CI 0.35 to 1.95), atherosclerotic cardiovascular mortality (RR 0.49; 95% CI 0.21 to 1.13), and any atherosclerotic cardiovascular event (RR 0.63; 95% CI 0.40 to 0.98). Among 320 subjects who used non-statin drug therapies, the RRs were 0.66 (95% CI 0.45 to 0.97) for recurrent coronary events, 0.95 (95% CI 0.46 to 1.95) for stroke, 0.68 (95% CI 0.35 to 1.32) for cardiovascular mortality, and 0.77 (95% CI 0.53 to 1.11) for any atherosclerotic cardiovascular event, compared with untreated hyperlipidemic patients. CONCLUSIONS: In this study of MI survivors, the use of lipid-lowering drug therapies after hospitalization was associated with a reduced risk of cardiovascular events. These results emphasize the importance of lipid-lowering drug treatment in patients with hyperlipidemia who survive a first MI.