Vitamin E linked to increased risk of heart failure

The results of a seven-year study examining the potential benefit of vitamin E in preventing cancer and cardiovascular events in older patients with vascular disease or Diabetes not only showed no benefit from taking the supplement, it showed an increased risk of heart failure, according to a report in the Journal of the American Medical Association.

The original HOPE (Heart Outcomes Prevention Evaluation) trial found no evidence that vitamin E affects the outcome of Heart disease after 4.5 years. The study included approximately 9,500 patients, 55 years of age or older, with vascular disease or diabetes assigned to a placebo or 400 IU per day of vitamin E.

Thinking that the treatment period may have been too short to show a benefit, Dr. Eva Lonn, at McMaster University in Hamilton, Ontario, and colleagues, extended the HOPE study for 2.5 more years. In HOPE-The Ongoing Outcomes (HOPE-TOO) trial, nearly 4,000 subjects continued in the trial.

There were no significant differences between the vitamin E group and the placebo group in cancer rate, cancer deaths, major cardiovascular events (heart attack, stroke, or death from cardiovascular causes), or death from any cause in the extension study.

However, the risk of heart failure was higher in the vitamin E group than in the placebo group (14.7 percent versus 12.6 percent), as was the risk of hospitalization for heart failure (5.8 percent versus 4.2 percent).

"In conjunction with its lack of efficacy, the potential for harm suggested by our findings strongly supports the view that vitamin E supplements should not be used in patients with vascular disease or diabetes mellitus," Lonn's group advises.

"HOPE-TOO reemphasizes the importance of controlled clinical trials for testing important hypotheses deriving from basic biological findings or from epidemiological observations," Dr. B. Greg Brown and Dr. John Crowley, at the University of Washington in Seattle, write in an accompanying editorial.

SOURCE: Journal of the American Medical Association, March 16, 2005.