A cooperative trial in the primary prevention of ischaemic heart disease using clofibrate: Some statistical aspects

Abstract

Some results of the primary prevention trial using clofibrate not published in the original report are presented. After showing that the entry characteristics of the “dropouts” in the treated group and in the main control group were similar, the emphasis is on deaths from causes other than ischaemic heart disease in the trial and within 1 year of leaving it. Such deaths occured no earlier, in terms of time since entry to the trial, in the clofibrate-treated group than in the main control group; they were no less frequent in those men in the treated group who were shown in the earlier report to have the greatest reduction in nonfatal myocardial infarction than in the remainder; and they showed no clear relationship with cholesterol reduction during the trial. Death rates calculated by the indirect method of age-standardization are presented and are preferred to the published rates calculated by the direct method. All men in the trial were followed to the end of 1978 to ascertain survival or cause of death. This will provide much larger numbers on many of the issues discussed here.