Incidence of new coronary events in older persons with prior myocardial infarction and serum low-density lipoprotein cholesterol ≥125 mg/dl treated with statins versus no lipid-lowering drug

Abstract

O lder persons with hypercholesterolemia or increased serum low-density lipoprotein (LDL) or low serum high-density lipoprotein (HDL) cholesterol levels are at increased risk for new coronary events. Older persons with coronary artery disease (CAD) and elevated serum LDL cholesterol treated with simvastatin or pravastatin had a significant reduction in new coronary events. We are reporting data from an observational study investigating the effects of statins on the incidence of new coronary events in older men and women with prior myocardial infarction and a serum LDL cholesterol 125 mg/dl followed prospectively for the incidence of new coronary events. • • • Four hundred eighty-eight men and 922 women, mean age 81 9 years (range 60 to 100), with prior myocardial infarction and a serum LDL cholesterol 125 mg/dl treated with a statin or with no lipidlowering drug were followed prospectively in a longterm health care facility for the incidence of new coronary events. Persons were considered to have prior myocardial infarction if they had a documented clinical history of myocardial infarction or electrocardiographic evidence of Q-wave myocardial infarction. New coronary events were diagnosed if the person developed nonfatal or fatal myocardial infarction or sudden coronary death as previously described. Systemic hypertension was diagnosed according to the criteria of the Sixth Joint National Committee Report on the Detection, Evaluation, and Treatment of Hypertension. All persons with hypertension were treated with antihypertensive therapy. Diabetes mellitus was diagnosed according to the American Diabetes Association’s new criteria. Measurements of fasting serum lipids were obtained in all persons after a 12to 14-hour overnight fast at baseline, after 1 month of therapy, and every 6 months during the study. A serum LDL cholesterol 125 mg/dl was considered elevated. A serum HDL cholesterol 35 mg/dl was considered decreased. A serum triglyceride level 190 mg/dl was considered increased. A person was considered obese if the body mass index was 30 kg/m. The full-time staff physicians involved in the study treated 679 of 1,410 persons (48%) with a statin and 731 (52%) with no lipid-lowering drug. The attitude of different physicians toward treating hypercholesterolemia in older persons with prior myocardial infarction determined whether statins were prescribed. Persons were followed until the time of a new coronary event, death, or cutoff date analysis of data. Follow-up was 36 21 months (range 1 to 133). Chi-square tests were used to analyze dichotomous variables and Student’s t tests for continuous variables (Tables 1 to 4). Table 5 lists the prognostic variables for new coronary events and their regression coefficients in the stepwise Cox regression model. The Cochran-Armitage test was used to examine if there was a trend in the reduction of new coronary events in persons treated with statins as the last level of serum LDL cholesterol decreased (Table 6). Table 1 lists baseline characteristics of those treated with statins versus no lipid-lowering drugs and lists levels of statistical significance. Table 2 lists the baseline and last follow-up serum lipids in persons treated with statins versus no lipid-lowering drugs and lists levels of statistical significance. Table 3 shows the incidence of new coronary events in persons treated with statins versus no lipid-lowering drugs and lists the level of statistical significance. Table 5 shows the prognostic variables for new coronary events and their regression coefficients in the stepwise Cox regression model. Table 4 shows the incidence of new coronary events in persons treated with statins versus no lipid-lowering drugs for the age groups of 60 to 70, 71 to 80, 81 to 90, and 91 to 100 years, and lists levels of statistical significance. Table 6 shows the incidence of new coronary events in persons treated with statins From the Department of Medicine, Westchester Medical Center/New York Medical College, Valhalla, New York; and the Division of Clinical Epidemiology, University of Texas Medical School at Houston, Houston, Texas. Dr. Aronow’s address is: Department of Medicine, Westchester Medical Center/New York Medical College, 23 Pebble Way, New Rochelle, New York 10804. Manuscript received July 30, 2001; revised manuscript received and accepted September 4, 2001. TABLE 1 Baseline Characteristics of Persons With Prior Myocardial Infarction and Elevated Serum LDL Cholesterol Treated With Statins Versus No Lipid-Lowering Drug