Current cholesterol guidelines can prevent a significant proportion of deaths and recurrent heart attacks in people with existing heart disease, according to researchers at the University of California, San Francisco.
The guidelines, however, can prevent only a modest proportion of first-time heart attacks, the researchers report in the September 1 issue of the Journal of the American College of Cardiology.
Using a computer simulation of 35- to 84-year-old Americans, the researchers measured the projected impact of the National Cholesterol Education Program (NCEP) guidelines between the years 2000 and 2020. They found that people with heart disease can expect to reap greater benefits from lowering their cholesterol levels than people without heart disease, in terms of decreasing heart attacks and heart disease deaths and increasing years of life.
"Many people have assumed that lowering cholesterol levels before the onset of heart disease would have a powerful effect as a primary prevention tool," said Lee Goldman, MD, MPH, FACC, UCSF professor of medicine and lead author of the study. "Our results show that secondary prevention, or lowering cholesterol levels after being diagnosed with heart disease, has an even greater impact." For people with existing heart disease, the NCEP guidelines suggest low density lipoprotein (LDL) cholesterol levels should be at 100 milligrams per deciliter of blood (mg/dL). For people without known heart disease, the guidelines suggest LDL levels should be at 130 mg/dL or 160 mg/dL, depending on the status of risk factors such as diabetes, smoking habits, and age.
Between 60 to 75 percent of the epidemiologic benefits derived from lowering cholesterol levels, assuming full compliance of the guidelines, were projected to affect people already diagnosed with heart disease, said Goldman. Lower levels of cholesterol in this population were projected to result in 60 percent of the overall decrease of heart attacks and nearly 80 percent of the overall decrease in deaths in both men and women over the 21-year study period. These greater benefits would require only half as many years of treatment, said Goldman, making it more cost-effective to emphasize secondary prevention.
"Targeting people who already have heart disease makes sense from a public health perspective," said Goldman. "There are more benefits with fewer costs and the likelihoods of implementation by physicians and compliance by patients are far higher."
In addition to Goldman, co-authors of the paper include Pamela Coxson, PhD, UCSF specialist, department of medicine; Maria Hunink, MD, PhD, department of health sciences, University of Groningen, the Netherlands; Paula Goldman, MPH, department of health policy and management, Harvard School of Public Health; Anna Tosteson, ScD, department of clinical research, Dartmouth Hitchcock Medical Center; Murray Mittleman, MDCM, DrPh, Beth Israel Deaconess Medical Center and Harvard Medical School; Lawrence Williams, MS, Brigham and Women's Hospital; and Milton Weinstein, PhD, department of health policy and management, Harvard School of Public Health.
Journal
Journal of the American College of Cardiology