From the Department of Neurology, University of Southern California, Los Angeles (B.A., A.T.); Department of Neurology, Rancho Los Amigos National Rehabilitation Center, Downey, CA (B.A., A.T.); Department of Neurosciences, Medical University of South Carolina, Charleston (B.O.); Department of Biomathematics, University of California, Los Angeles (D.M.); and Department of Neurology, University of Toronto, Toronto, Ontario, Canada (G.S.).
Stroke. 2015 Mar;46(3):870-3. doi: 10.1161/STROKEAHA.114.006927. Epub 2015 Feb 3.
Although several randomized controlled trials failed to show a benefit of B vitamin therapy on composite outcomes of cardiovascular death, myocardial infarction, and stroke among individuals with elevated homocysteine, recent post hoc analyses have suggested that several factors may interact with the effects of vitamin treatment. One post hoc analysis revealed an interaction between B vitamin therapy and antiplatelet use; however, those results have not been replicated in other studies or populations.
We conducted a post hoc analysis of the Vitamin Intervention for Stroke Prevention (VISP) trial, a randomized controlled trial evaluating treatment with high- versus low-dose B vitamin therapy for secondary prevention of vascular events among stroke survivors with elevated homocysteine. Cox regression models were used to assess primary (recurrent stroke) and secondary (stroke, myocardial infarction, or vascular death) outcomes among individuals on high- versus low-dose vitamin therapy, categorized by antiplatelet use, after adjusting for covariates.
Among 3680 participants, 52% took antiplatelet medications. When compared with low-dose therapy, high-dose vitamin therapy was associated with higher stroke risk among individuals on antiplatelets (hazard ratio, 1.43; 95% confidence interval, 1.02-2.01), but trended toward lower risk among those not on antiplatelets (hazard ratio, 0.86; 95% confidence interval, 0.62-1.19).
High-dose B vitamin therapy may be associated with a higher risk of recurrent stroke among stroke survivors taking antiplatelets, but does not have a significant effect on recurrent stroke risk in those who are not on antiplatelets. Future randomized controlled trials may consider evaluating the effect of homocysteine lowering among stroke survivors with elevated homocysteine who are not on antiplatelet therapy.
尽管几项随机对照试验未能显示高同型半胱氨酸血症患者的 B 族维生素治疗对心血管死亡、心肌梗死和中风复合结局的益处，但最近的事后分析表明，有几个因素可能与维生素治疗的效果相互作用。一项事后分析显示 B 族维生素治疗与抗血小板治疗之间存在相互作用；然而，这些结果在其他研究或人群中尚未得到复制。
我们对维生素干预预防中风试验（VISP）进行了事后分析，这是一项随机对照试验，评估了高剂量与低剂量 B 族维生素治疗对高同型半胱氨酸血症中风幸存者血管事件的二级预防作用。使用 Cox 回归模型评估了接受高剂量与低剂量维生素治疗的个体的主要（复发性中风）和次要（中风、心肌梗死或血管死亡）结局，这些个体根据抗血小板药物的使用情况进行了分类，并在调整了协变量后进行了评估。
在 3680 名参与者中，有 52%的人服用抗血小板药物。与低剂量治疗相比，高剂量维生素治疗与服用抗血小板药物的个体中风风险增加相关（风险比，1.43；95%置信区间，1.02-2.01），但在未服用抗血小板药物的个体中，风险呈下降趋势（风险比，0.86；95%置信区间，0.62-1.19）。
高剂量 B 族维生素治疗可能与服用抗血小板药物的中风幸存者复发性中风风险增加相关，但对未服用抗血小板药物的中风幸存者复发性中风风险无显著影响。未来的随机对照试验可能需要考虑评估未服用抗血小板药物的高同型半胱氨酸血症中风幸存者的同型半胱氨酸降低的效果。
