Joel G. Ray, MD, MSc; Clive Kearon, MD, PhD; Qilong Yi, PhD; Patrick Sheridan, MSc; Eva Lonn, MD, MSc; for the Heart Outcomes Prevention Evaluation 2 (HOPE-2) Investigators*
Grant Support: In part by a Canadian Institutes of Health Research grant (MT-15418) and by Jamieson Laboratories, Toronto, Ontario, Canada. Dr. Ray is supported by a Canadian Institutes for Health Research New Investigator Award.
Potential Financial Conflicts of Interest: None disclosed.
Requests for Single Reprints: Joel G. Ray, MD, MSc, Department of Medicine, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada; e-mail, email@example.com.
Current Author Addresses: Dr. Ray: Department of Medicine, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada.
Dr. Kearon: 70 Wing, Room 39, Henderson General Hospital, 711 Concession Street, Hamilton, Ontario L8V 1C3, Canada.
Drs. Yi and Lonn and Mr. Sheridan: Population Health Research Institute, Hamilton General Hospital, 237 Barton Street East, Hamilton, Ontario L8L 2X2, Canada.
Author Contributions: Conception and design: J.G. Ray, E. Lonn.
Analysis and interpretation of the data: J.G. Ray, C. Kearon, Q. Yi, E. Lonn.
Drafting of the article: J.G. Ray, C. Kearon, E. Lonn.
Critical revision of the article for important intellectual content: J.G. Ray, C. Kearon, E. Lonn.
Final approval of the article: J.G. Ray, C. Kearon, E. Lonn.
Provision of study materials or patients: E. Lonn.
Statistical expertise: Q. Yi, P. Sheridan.
Obtaining of funding: E. Lonn.
Administrative, technical, or logistic support: J.G. Ray, P. Sheridan, E. Lonn.
Collection and assembly of data: P. Sheridan, E. Lonn.
Elevated total homocysteine levels are associated with a higher risk for venous thromboembolism. Whether decreasing homocysteine levels with vitamin therapy reduces the risk for venous thromboembolism is not known.
To determine whether decreasing homocysteine levels alters the risk for symptomatic venous thromboembolism.
Secondary analysis of data from the randomized, placebo-controlled Heart Outcomes Prevention Evaluation 2 (HOPE-2) trial.
145 clinical centers in 13 countries.
5522 persons 55 years of age or older with known cardiovascular disease or diabetes mellitus and at least 1 other risk factor for vascular disease.
A daily supplement of 2.5 mg of folic acid, 50 mg of vitamin B6, and 1 mg of vitamin B12 or matching placebo for 5 years.
Prospectively diagnosed and confirmed symptomatic deep venous thrombosis or pulmonary embolism.
The geometric mean homocysteine level decreased by 2.2 µmol/L in the vitamin therapy group and increased by 0.80 µmol/L in the placebo group. Venous thromboembolism occurred in 88 participants during a mean follow-up of 5 years. The incidence rate of venous thromboembolism was the same in the vitamin therapy group and the placebo group (0.35 per 100 person-years; hazard ratio, 1.01 [95% CI, 0.66 to 1.53]). Vitamin therapy did not reduce the risk for deep venous thrombosis (hazard ratio, 1.04 [CI, 0.63 to 1.72]), pulmonary embolism (hazard ratio, 1.14 [CI, 0.57 to 2.28]), or unprovoked venous thromboembolism (hazard ratio, 1.21 [CI, 0.66 to 2.23]).
The proportion of patients with a previous episode of venous thromboembolism at enrollment was not known, and venous thromboembolism events were not centrally adjudicated.
Decreasing homocysteine levels with folic acid and vitamins B6 and B12 did not reduce the risk for symptomatic venous thromboembolism.
*For a list of the HOPE-2 investigators, see the Appendix.
ClinicalTrials.gov registration number: NCT00106886.
Current Controlled Trials registration number: ISRCTN14017017.
In observational studies, elevated plasma homocysteine levels were associated with venous thromboembolism. A multicenter trial of folic acid and B vitamins to reduce cardiovascular events investigated the effect of homocysteine lowering on venous thromboembolism.
In this trial, 5522 adults were randomly assigned to receive placebo, or folic acid and vitamins B6 and B12 daily for 5 years. Vitamin therapy decreased homocysteine levels, but the incidence of venous thromboembolism was the same in both groups, even in participants with the highest levels of homocysteine.
Venous thromboembolism events were not centrally adjudicated.
Decreasing homocysteine levels with supplements containing folic acid and vitamins B6 and B12 does not reduce the incidence of venous thromboembolism.
Risk for venous thromboembolism (VTE) in prespecified subgroups.
Table 1. Baseline Characteristics*
Table 2. Rate of Venous Thromboembolism
Cumulative proportion of participants with venous thromboembolism.
Appendix Table. Baseline Characteristics of Participants Who Did and Did Not Have Plasma Homocysteine Measured at Baseline*
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Joel G. Ray, Clive Kearon, Qilong Yi, Patrick Sheridan, Eva Lonn, . Homocysteine-Lowering Therapy and Risk for Venous Thromboembolism: A Randomized Trial. Ann Intern Med. 2007;146:761–767. doi: 10.7326/0003-4819-146-11-200706050-00157
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Published: Ann Intern Med. 2007;146(11):761-767.
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