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Original Contribution
August 20, 2008

Mortality and Cardiovascular Events in Patients Treated With Homocysteine-Lowering B Vitamins After Coronary Angiography: A Randomized Controlled Trial

Author Affiliations

Author Affiliations: Department of Heart Disease, Haukeland University Hospital (Drs Ebbing, Bleie, Nordrehaug, and Nygård), Sections for Pharmacology (Dr Ueland) and Cardiology (Drs Nordrehaug, Nilsen, Ringdal Pedersen, and Nygård), Institute of Medicine, University of Bergen and Haukeland University Hospital, and Department of Public Health and Primary Health Care, University of Bergen (Dr Vollset), Bergen, Norway; Department of Cardiology, Stavanger University Hospital, Stavanger, Norway (Dr Nilsen); Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway (Dr Refsum); and Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, England (Dr Refsum).

JAMA. 2008;300(7):795-804. doi:10.1001/jama.300.7.795
Abstract

Context Observational studies have reported associations between circulating total homocysteine concentration and risk of cardiovascular disease. Oral administration of folic acid and vitamin B12 can lower plasma total homocysteine levels.

Objective To assess the effect of treatment with folic acid and vitamin B12 and the effect of treatment with vitamin B6 as secondary prevention in patients with coronary artery disease or aortic valve stenosis.

Design, Setting, and Participants Randomized, double-blind controlled trial conducted in the 2 university hospitals in western Norway in 1999-2006. A total of 3096 adult participants undergoing coronary angiography (20.5% female; mean age, 61.7 years) were randomized. At baseline, 59.3% had double- or triple-vessel disease, 83.7% had stable angina pectoris, and 14.9% had acute coronary syndromes.

Interventions Using a 2 × 2 factorial design, participants were randomly assigned to 1 of 4 groups receiving daily oral treatment with folic acid, 0.8 mg, plus vitamin B12, 0.4 mg, plus vitamin B6, 40 mg (n = 772); folic acid plus vitamin B12 (n = 772); vitamin B6 alone (n = 772); or placebo (n = 780).

Main Outcome Measures The primary end point was a composite of all-cause death, nonfatal acute myocardial infarction, acute hospitalization for unstable angina pectoris, and nonfatal thromboembolic stroke.

Results Mean plasma total homocysteine concentration was reduced by 30% after 1 year of treatment in the groups receiving folic acid and vitamin B12. The trial was terminated early because of concern among participants due to preliminary results from a contemporaneous Norwegian trial suggesting adverse effects from the intervention. During a median 38 months of follow-up, the primary end point was experienced by a total of 422 participants (13.7%): 219 participants (14.2%) receiving folic acid/vitamin B12 vs 203 (13.1%) not receiving such treatment (hazard ratio, 1.09; 95% confidence interval, 0.90-1.32; P = .36) and 200 participants (13.0%) receiving vitamin B6 vs 222 (14.3%) not receiving vitamin B6 (hazard ratio, 0.90; 95% confidence interval, 0.74-1.09; P = .28).

Conclusions This trial did not find an effect of treatment with folic acid/vitamin B12 or vitamin B6 on total mortality or cardiovascular events. Our findings do not support the use of B vitamins as secondary prevention in patients with coronary artery disease.

Trial Registration clinicaltrials.gov Identifier: NCT00354081

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