Four large trials have shown cholesterol-reduction therapy to be effective for primary prevention of coronary heart disease (CHD).
To determine the generalizability of these trials to a community-based sample, we compared the total cholesterol and high-density lipoprotein cholesterol (HDL-C) distributions of patients in the 4 trials with those of Framingham Heart Study subjects. Lipid profiles that have not been studied were identified. Twelve-year rates of incident CHD were compared between subjects who met eligibility criteria and those who did not.
The Framingham sample included 2498 men and 2870 women aged 30 to 74 years. Among Framingham men, 23.4% to 42.0% met eligibility criteria for each of the 4 trials based on their lipid levels; 60.2% met eligibility criteria for at least 1 trial. For the 1 trial that included women, 20.2% of Framingham women met eligibility criteria. In general, subjects with desirable total cholesterol levels and lower HDL-C levels and subjects with average total cholesterol levels and average to higher HDL-C levels have not been included in these trials. Among subjects who developed incident CHD during follow-up, 25.1% of men and 66.2% of women would not have been eligible for any trial. Most ineligible subjects who developed CHD had isolated hypertriglyceridemia (>2.25 mmol/L [>200 mg/dL]).
In our sample, 40% of men and 80% of women had lipid profiles that have not been studied in large trials to date. We observed a large number of CHD events in "ineligible" subjects in whom hypertriglyceridemia was common. Further studies are needed to define the role of lipid-lowering therapy vs other strategies for primary prevention in the general population.