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Homocysteine-Lowering Therapy: Another Negative Study

No benefits were found with folic acid, vitamin B₁₂, or vitamin B₆ supplementation.

In several large randomized prevention trials, homocysteine-lowering vitamin therapy has not improved outcomes among patients with coronary artery disease or cardiovascular risk factors. In this latest study, Norwegian researchers enrolled 3090 patients with stable angina or acute coronary syndromes who were scheduled for coronary angiography. About two thirds of the patients subsequently underwent percutaneous coronary revascularization or coronary bypass surgery. Patients were randomized to one of four vitamin supplementation groups: folic acid plus vitamin B₁₂ plus vitamin B₆, folic acid plus vitamin B₁₂, vitamin B₆ only, or placebo.

At baseline, mean plasma total homocysteine level was 11 µmol/L, and levels decreased by 30% in the groups that received folic acid and vitamin B₁₂. During a median follow-up of 38 months, the primary composite endpoint (death, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for unstable angina) occurred in 14% of patients overall. The incidence of the endpoint was not significantly different among patients who received folate and B₁₂ compared with those who did not or among patients who received B₆ compared with those who did not. None of the four individual components of the composite endpoint were influenced favorably by vitamin supplementation.

Comment: This is the fifth consecutive large trial that has shown no benefit for homocysteine-lowering B-vitamin supplementation among patients with cardiovascular disease or cardiac risk factors and homocysteine levels that are normal or mildly-to-moderately elevated (e.g., JW May 6 2008). In my experience, some clinicians continue to prescribe brand-name B-vitamin supplements to such patients, at a cost of hundreds of dollars annually. This practice can no longer be justified.

— Allan S. Brett, MD

Published in Journal Watch General Medicine August 19, 2008

Citation(s):

Ebbing M et al. Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography: A randomized controlled trial. JAMA 2008 Aug 20; 300:795.

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