Tags

Type your tag names separated by a space and hit enter

Homocysteine-lowering trials for prevention of cardiovascular events: a review of the design and power of the large randomized trials.
Am Heart J 2006; 151(2):282-7AH

Abstract

BACKGROUND

Dietary supplementation with folic acid and vitamin B12 lowers blood homocysteine concentrations by about 25% to 30% in populations without routine folic acid fortification of food and by about 10% to 15% in populations with such fortification. In observational studies, 25% lower homocysteine has been associated with about 10% less coronary heart disease (CHD) and about 20% less stroke.

METHODS

We reviewed the design and statistical power of 12 randomized trials assessing the effects of lowering homocysteine with B-vitamin supplements on risk of cardiovascular disease.

RESULTS

Seven of these trials are being conducted in populations without fortification (5 involving participants with prior CHD and 2 with prior stroke) and 5 in populations with fortification (2 with prior CHD, 2 with renal disease, and 1 with prior stroke). These trials may not involve sufficient number of vascular events or last long enough to have a good chance on their own to detect reliably plausible effects of homocysteine lowering on cardiovascular risk. But, taken together, these 12 trials involve about 52,000 participants: 32,000 with prior vascular disease in unfortified populations and 14,000 with vascular disease and 6000 with renal disease in fortified populations. Hence, a combined analysis of these trials should have adequate power to determine whether lowering homocysteine reduces the risk of cardiovascular events within just a few years.

CONCLUSION

The strength of association of homocysteine with risk of cardiovascular disease may be weaker than had previously been believed. Extending the duration of treatment in these trials would allow any effects associated with prolonged differences in homocysteine concentrations to emerge. Establishing a prospective meta-analysis of the ongoing trials of homocysteine lowering should ensure that reliable information emerges about the effects of such interventions on cardiovascular disease outcomes.

Authors

No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Review

Language

eng

PubMed ID

16442889

Citation

B-Vitamin Treatment Trialists' Collaboration. "Homocysteine-lowering Trials for Prevention of Cardiovascular Events: a Review of the Design and Power of the Large Randomized Trials." American Heart Journal, vol. 151, no. 2, 2006, pp. 282-7.
B-Vitamin Treatment Trialists' Collaboration. Homocysteine-lowering trials for prevention of cardiovascular events: a review of the design and power of the large randomized trials. Am Heart J. 2006;151(2):282-7.
B-Vitamin Treatment Trialists' Collaboration. (2006). Homocysteine-lowering trials for prevention of cardiovascular events: a review of the design and power of the large randomized trials. American Heart Journal, 151(2), pp. 282-7.
B-Vitamin Treatment Trialists' Collaboration. Homocysteine-lowering Trials for Prevention of Cardiovascular Events: a Review of the Design and Power of the Large Randomized Trials. Am Heart J. 2006;151(2):282-7. PubMed PMID: 16442889.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Homocysteine-lowering trials for prevention of cardiovascular events: a review of the design and power of the large randomized trials. A1 - ,, PY - 2004/11/25/received PY - 2005/04/26/accepted PY - 2006/1/31/pubmed PY - 2006/2/14/medline PY - 2006/1/31/entrez SP - 282 EP - 7 JF - American heart journal JO - Am. Heart J. VL - 151 IS - 2 N2 - BACKGROUND: Dietary supplementation with folic acid and vitamin B12 lowers blood homocysteine concentrations by about 25% to 30% in populations without routine folic acid fortification of food and by about 10% to 15% in populations with such fortification. In observational studies, 25% lower homocysteine has been associated with about 10% less coronary heart disease (CHD) and about 20% less stroke. METHODS: We reviewed the design and statistical power of 12 randomized trials assessing the effects of lowering homocysteine with B-vitamin supplements on risk of cardiovascular disease. RESULTS: Seven of these trials are being conducted in populations without fortification (5 involving participants with prior CHD and 2 with prior stroke) and 5 in populations with fortification (2 with prior CHD, 2 with renal disease, and 1 with prior stroke). These trials may not involve sufficient number of vascular events or last long enough to have a good chance on their own to detect reliably plausible effects of homocysteine lowering on cardiovascular risk. But, taken together, these 12 trials involve about 52,000 participants: 32,000 with prior vascular disease in unfortified populations and 14,000 with vascular disease and 6000 with renal disease in fortified populations. Hence, a combined analysis of these trials should have adequate power to determine whether lowering homocysteine reduces the risk of cardiovascular events within just a few years. CONCLUSION: The strength of association of homocysteine with risk of cardiovascular disease may be weaker than had previously been believed. Extending the duration of treatment in these trials would allow any effects associated with prolonged differences in homocysteine concentrations to emerge. Establishing a prospective meta-analysis of the ongoing trials of homocysteine lowering should ensure that reliable information emerges about the effects of such interventions on cardiovascular disease outcomes. SN - 1097-6744 UR - https://www.unboundmedicine.com/medline/citation/16442889/Homocysteine_lowering_trials_for_prevention_of_cardiovascular_events:_a_review_of_the_design_and_power_of_the_large_randomized_trials_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0002-8703(05)00444-8 DB - PRIME DP - Unbound Medicine ER -