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May 26, 1989

Randomized Clinical Trials in Heart Disease

Author Affiliations

University of Toronto (Canada)

University of Toronto (Canada)

JAMA. 1989;261(20):2953. doi:10.1001/jama.1989.03420200042020

To the Editor.—  A recent article in JAMA by Yusuf et al1 reviewed a large number of trials of interventions for lowering cholesterol levels for the primary and secondary prevention of coronary heart disease. The article states that "there was no apparent heterogeneity in reduction of coronary heart disease observed in the drug or dietary intervention trials, in the primary prevention or secondary prevention trials, or on fatal or nonfatal coronary heart disease events." We are unable to comment fully on these assertions as the analysis on which they are based has not been published. However, there is evidence of clinically important differences between trials. For example, in a published work by Yusuf and Furberg,2 the aggregate risk ratio for coronary heart disease mortality in trials of dietary intervention was 0.99, while aggregation of the trials of lipid-lowering pharmaceutical agents showed a reduction in cardiac mortality for treated