The West of Scotland Coronary Prevention Study [1] demonstrated that pravastatin prevented myocardial infarction and cardiovascular death in asymptomatic men with high low-density lipoprotein (LDL) cholesterol levels. Since publication of this and other trials, statins have become the primary antidyslipidemic agents prescribed in the United States despite the proven benefit of gemfibrozil and niacin. For example, the Helsinki Heart Study (HHS) showed that gemfibrozil prevented myocardial infarction in asymptomatic men at high risk for coronary artery disease [2].

I reanalyzed the West of Scotland study and HHS with the number needed to treat (NNT) concept. The latter measure is defined as the number of patients who need to be treated for a given duration to prevent one event [3]. It is the reciprocal of the absolute risk reduction.

The West of Scotland study found that 52 (95% CI, 37 to 115; P < 0.05) men with LDL cholesterol levels greater than 155 mg/dL need to be treated for 5 years to prevent a myocardial infarction. In the HHS, the corresponding NNT was 42 (CI, 28 to 268; P < 0.05) men with triglyceride levels greater than 174 mg/dL. The benefit of gemfibrozil was smaller in men with triglyceride levels less than 174 mg/dL (NNT, 119 [CI, –168 to 57; the negative NNT indicates that the CI includes the possibility that 1 person could have a myocardial infarction for every 168 treated]). The inclusion of men with triglyceride levels less than 174 mg/dL in the HHS may explain the lack of overall effect of gemfibrozil on mortality (only 37% of the men in the HHS had triglyceride levels >174 mg/dL).

The benefit from gemfibrozil in men with high triglyceride levels may result from gemfibrozil's increasing LDL particle size or increasing high-density lipoprotein cholesterol (HDL) levels. Statins are less effective than gemfibrozil in altering LDL size or HDL cholesterol levels. Gemfibrozil may also have a role in secondary or tertiary prevention. The LOCAT (Lopid Coronary Angiography Trial) investigators showed that gemfibrozil reduced progression of coronary atherosclerosis in patients who had undergone coronary artery bypass grafting and had low HDL cholesterol levels (<42.5 mg/dL) [4].

Treatment of dyslipidemia should be individualized. Statins have been proven to prevent coronary events in men with LDL cholesterol levels greater than 155 mg/dL. Gemfibrozil is equally efficacious in preventing myocardial infarction in high-risk men with low HDL cholesterol levels and triglyceride levels greater than 174 mg/dL.