Efficacy of a Chronic Care-Based Intervention on Secondary Stroke Prevention Among Vulnerable Stroke Survivors: A Randomized Controlled Trial.

BACKGROUND: Disparities of care among stroke survivors are well documented. Effective interventions to improve recurrent stroke preventative care in vulnerable populations are lacking. METHODS AND RESULTS: In a randomized controlled trial, we tested the efficacy of components of a chronic care model-based intervention versus usual care among 404 subjects having an ischemic stroke or transient ischemic attack within 90 days of enrollment and receiving care within the Los Angeles public healthcare system. Subjects had baseline systolic blood pressure (SBP) ≥120 mm Hg. The intervention included a nurse practitioner/physician assistant care manager, group clinics, self-management support, report cards, decision support, and ongoing care coordination. Outcomes were collected at 3, 8, and 12 months, analyzed as intention-to-treat, and used repeated-measures mixed-effects models. Change in SBP was the primary outcome. Low-density lipoprotein reduction, antithrombotic medication use, smoking cessation, and physical activity were secondary outcomes. Average age was 57 years; 18% were of black race; 69% were of Hispanic ethnicity. Mean baseline SBP was 150 mm Hg in both arms. SBP decreased to 17 mm Hg in the intervention arm and 14 mm Hg in the usual care arm; the between-arm difference was not significant (-3.6 mm Hg; 95% confidence interval, -9.2 to 2.2). Among secondary outcomes, the only significant difference was that persons in the intervention arm were more likely to lower their low-density lipoprotein <100 md/dL (2.0 odds ratio; 95% confidence interval, 1.1-3.5). CONCLUSIONS: This intervention did not improve SBP control beyond that attained in usual care among vulnerable stroke survivors. A community-centered component could strengthen the intervention impact. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT00861081.

Effect of B-vitamins on stroke risk among individuals with vascular disease who are not on antiplatelets: A meta-analysis.

BACKGROUND: Retrospective analyses of randomized controlled trials suggest that antiplatelet therapy may modify the potential cerebrovascular benefits of lowering homocysteine with B-vitamins among individuals with cardiovascular disease. We evaluated the effects of B-vitamin supplementation on risk of subsequent stroke among high cardiovascular risk individuals who are not taking antiplatelet medications. METHODS: We systematically searched the Cochrane Central Register of controlled trials, PubMed, the Internet Stroke Center stroke trials, and the clinical trials.gov website from 1966 to April 2015. Inclusion criteria included: randomized controlled trials of homocysteine-lowering therapy with B-vitamins; high cardiovascular risk population and follow-up ≥1 year. We considered stroke as the primary outcome. Among 11 randomized controlled trials meeting inclusion criteria, three studies assessed stroke as an outcome and reported event rates according to whether or not individuals were taking antiplatelets: Vitamin Intervention for Stroke Prevention (VISP), VITAmins TO Prevent Stroke (VITATOPS), and Heart Outcomes Prevention Evaluation 2 (HOPE-2). RESULTS: A total of 4643 high vascular risk subjects not taking antiplatelets were evaluated. The overall effect size across studies was summarized using the fixed effects model after confirming there was no significant heterogeneity. Heterogeneity was assessed using the Cochran's Q and I(2) statistics. Compared with the control group, those taking B-vitamin supplementation had a lower risk of recurrent stroke (HR 0.86, 95% CI 0.62 to 1.19 for VISP; 0.65, 0.46 to 0.91 for VITATOPS; and 0.60, 0.39 to 0.92 for HOPE-2; overall HR 0.71, 0.58 to 0.88). CONCLUSION: Homocysteine lowering with B-vitamins among high vascular risk patients who are not taking antiplatelet therapy is related to a significant reduction (29%) in overall stroke risk. A clinical trial of B-vitamins in this group may be warranted.

Differential effect of B-vitamin therapy by antiplatelet use on risk of recurrent vascular events after stroke.

BACKGROUND AND PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Homocysteine-lowering therapy and risk of recurrent stroke, myocardial infarction and death: the impact of age in the VISP trial.

BACKGROUND: Clinical trials have failed to show a benefit of B vitamin therapy in reducing composite outcomes of cardiovascular death, myocardial infarction, and stroke among stroke survivors with elevated total serum homocysteine (tHcy) levels. Recent post hoc analyses have shown that numerous factors including age, baseline tHcy levels, folic acid fortification of grains, B12 status, renal function, comorbidities, and medications may modify the effect of B vitamin therapy on vascular risk in individuals with high tHcy. It remains possible that tHcy-lowering therapy may reduce cardiovascular risk in certain subgroups of stroke survivors. Post hoc subgroup analysis of the Heart Outcomes Prevention Evaluation-2 randomized controlled trial, which randomized participants with known cardiovascular disease to tHcy-lowering therapy or placebo, revealed larger treatment benefit for patients aged younger than 69 years; however, that analysis did not control for other factors. The aim of this study was to determine the effect of age on the impact of tHcy-lowering therapy for reducing vascular risk after stroke while controlling for other factors known to modify the effect of tHcy and tHcy-lowering therapy on vascular risk. METHODS: In this post hoc analysis of the Vitamin Intervention for Stroke Prevention (VISP) trial, a randomized controlled trial of tHcy lowering for secondary stroke prevention, we excluded individuals who had poor renal function (glomerular filtration rate <47; the 10th percentile) or were treated with vitamin B12 injections. We assessed the effects of high-dose vitamin replacement on primary (stroke, myocardial infarction, or death) and secondary (stroke) outcomes, after stratifying by age (< vs. ≥ median age, 67 years) and adjusting for demographic and clinical factors. RESULTS: This subgroup consisted of 2,993 individuals. Among individuals older than 67 years, high-dose vitamin therapy was associated with reduced risk of stroke, myocardial infarction or death (adjusted HR 0.76, 95% CI 0.58-0.99) and a trend towards reduced likelihood of stroke (adjusted HR 0.86, 95% CI 0.59-1.25). High-dose vitamin therapy did not impact outcomes among individuals younger than 67 years. CONCLUSIONS: In this post hoc subgroup analysis of the VISP trial, age modified the association between B vitamin therapy and recurrent vascular risk among stroke survivors with elevated serum tHcy levels. Older individuals with stroke were more likely to benefit from B vitamin therapy than younger individuals. These findings can help inform the future design of clinical trials of tHcy-lowering therapy for cardiovascular risk reduction after stroke. © 2014 S. Karger AG, Basel.