Study Weakens Case for Vitamin E Supplementation
Several randomized studies on the efficacy of the antioxidant in preventing cardiovascular events had previously been published. In a statement published in February 1999, the American Heart Association described the evidence on vitamin E as encouraging, at least for secondary prevention, but inconclusive.
HOPE was designed to overcome many of the limitations of the earlier studies. It was a large randomized, placebo-controlled trial designed to test the efficacy of two agentsramipril and vitamin Efor prevention of cardiovascular events in high-risk patients. The ramipril portion of the study was stopped in April 1999 when the benefits of ramipril became evident.
The patients enrolled in the study were at least 55 years of age and had cardiovascular disease or diabetes and one other risk factor for cardiovascular disease. About three fourths of the patients were men. Vitamin E was tested at a dosage of 400 IU daily, and treatment was continued for an average of 4.5 years.
The researchers reported finding no benefits from vitamin E supplementation. Of the 4761 patients assigned to receive vitamin E, 772 (16.2%) had a myocardial infarction or a stroke or died from cardiovascular causes, compared with 15.5% of patients in the placebo group, or 739 of 4780 patients. Thus, the relative risk of a cardiovascular event was 1.05 (95% confidence interval, 0.95-1.16) in the vitamin E group compared with the placebo group. The findings did not change when the frequencies of the three outcome variables (myocardial infarction, stroke, and death from cardiovascular causes) were examined separately. The results of other analyses performed by the investigators were consistent with the results of the primary analysis.
1. The Heart Outcomes Prevention Evaluation Study investigators. Vitamin E supplementation and cardiovascular events in high-risk patients. N Engl J Med. 2000; 342:154-60.