VIENNA -- Once again a major clinical trial using vitamins to lower homocysteine levels has failed to change clinical outcomes for patients with heart disease.
VIENNA, Sept. 5 -- Once again a major clinical trial using vitamins to lower homocysteine levels has failed to change clinical outcomes for patients with heart disease.
Norwegian researchers said that B vitamins were successful in lowering homocysteine levels in coronary patients, but the reduction had no apparent impact.
"Vitamin B supplementation is not justified as secondary prevention for coronary artery disease," said Marta Ebbing, M.D., of Haukeland University Hospital in Bergen, Norway, during the European Society of Cardiology meeting. "We saw no significant effect of B vitamins on death or cardiovascular events."
Dr. Ebbing and colleagues enrolled 3,090 heart patients who were undergoing coronary angiography into the Western Norway B-vitamin Intervention Trial (WENBIT).
In the study. 771 patients were assigned to homocysteine-lowering therapy with 0.8 mg daily doses of folic acid, 0.4 mg daily of Vitamin B12 and 40 mg of Vitamin B6. There were 771 patients who received B6 alone. There were 769 patients randomized to receive folic acid plus B12 and 779 patients to placebo.
The patients were compliant in taking their medication, illustrated by significantly-lowered homocysteine levels in the groups receiving folic acid and vitamin B12, Dr. Ebbing said. The levels were checked at one month, 12 months and at the end of the trial after median follow-up time of 38 months. There was about a 30% reduction in homocysteine.
The endpoint was a composite of mortality, non-fatal acute myocardial infarctions, unstable angina, and non-fatal stroke. Dr. Ebbing said there were 422 primary endpoint events.
There were 31 deaths among the patients on folic acid, B12, and B6. There were 33 deaths among those on folic acid and B12. There were 28 deaths among those on B6. And there were 25 deaths among those on placebo.
The design of the study compared those on folic acid - the homocysteine lowering regimen - against those not on folic acid and found a 10% greater relative risk of experiencing an event - a difference that failed to reach statistical significance (P=.35).
"WENBIT confirms and adds additional evidence to findings in similar trials that have shown no impact of lowering homocysteine," Dr. Ebbing said, but she refused to say that her study had finally put a stake into the concept that homocysteine has some impact on heart disease.
"For example," she said, "we still are not certain about a possible role in stroke." She said in her study there were only 56 strokes - with no significant difference among groups.
"The study appears to confirm what we know about homocysteine," said Freek Verheught, M.D., of the University Medical Center in Nijmegen, The Netherlands, who moderated the press briefing at which Dr. Ebbing's study was presented. "It may be a marker that there is some cardiovascular problem."
"The idea that one could cure our aliments by taking vitamins is appealing," said Daniel Jones, M.D., president of the American Heart Association, and dean of the School of Medicine at the University of Mississippi in Jackson, "but it hasn't worked out. We aren't any closer to understanding the role of homocysteine in cardiovascular disease today than we were 15 years ago when it was first suggested that levels of homocysteine were in some way related to the disease process."
He said it might be possible that starting children on increased doses of vitamins might have an impact later in life, but he said that study is unlikely to be done.
"Outside of a clinical trial, I have never ordered a test for homocysteine levels in a clinical setting and I don't plan to do so," Dr. Jones said.