Manfaat pemberian vitamin B pada penyakit jantung koroner

Suatu studi observasi melaporkan hubungan antara kadar homosistein dan risiko penyakit kardiovaskuler. Pemberian asam folat dan vitamin B12 diketahui dapat menurunkan kadar homosistein. Penelitian ini ingin mengetahui pengaruh asam folat dan vitamin B6 dan B12 untuk pencegahan sekunder pada pasien penyakit jantung koroner (PJK) dan stenosis klep aorta.

 

Penelitian dilakukan terhadap >3000 pasien yang menjalani prosedur angiografi dan berlangsung selama 7 tahun.

 

Setelah 1 tahun terjadi penurunan kadar homosistein kelompok yang mendapat asam folat dan vitamin B12. Tapi penurunan kadar homosistein ini tidak berpengaruh terhadap mortalitas dan cardiovascular events.

 

Kesimpulan penelitian ini tidak mendukung penggunaan vitamin B untuk preventif sekunder pasien dengan PJK.

 

Abstract

 

JAMA. Vol. 300 No. 7, August 20, 2008;300(7):795-804. © 2008 American Medical Association.
Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography.

Marta Ebbing, MD; Øyvind Bleie, MD, PhD; Per Magne Ueland, MD, PhD et al.

 

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 x 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.