No role for B12/folate post myocardial infarction

Homocysteine has been noted to be consistently higher in patients with occlusive vascular disease than in controls, and this difference is also seen prior to the onset of disease. Although previous large-scale randomised trials have failed to show any benefit from lowering homocysteine levels through the use of folic acid based supplements, the reasons for this have remained unclear, and subsequent subgroup analysis has suggested a protective effect on stroke. The SEARCH (Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine) trial examined the affects of lowering homocysteine levels using 2 mg of folic acid and 1 mg vitamin B12 daily.

The study followed 12 064 survivors of myocardial infarction who were assigned to either B12/folate or placebo. The main outcome measure was the first major vacular event, defined as a major coronary event (coronary death, myocardial infarction, or revascularisation), stroke, or noncoronary revascularisation.

Although allocation to the study vitamins reduced homocysteine levels by a mean of 3.8 umol/l (28%), over 6.7 years of follow-up no significant difference was noted in the incidence of major vascular events between the treatment and control groups (25.5% vs 24.8%; p=0.28). Furthermore there was no significant difference in the numbers of deaths attributed to vascular causes (9.6% vs 9.3%) or nonvascular causes (6.7% vs 6.5%). No adverse effect on cancer …