DÄ internationalArchive7/2008Secondary Stroke Prevention - Recent Advances: B Vitamins and Cerebral Ischemia

Correspondence

Secondary Stroke Prevention - Recent Advances: B Vitamins and Cerebral Ischemia

Dtsch Arztebl Int 2008; 105(7): 128-9. DOI: 10.3238/arztebl.2008.0128c

Lorenzl, S; Linnebank, M; Stanger, O

LNSLNS Diener et al., in their review of secondary prophylaxis of stroke, propose that four randomized studies had shown unequivocally that combination therapy with vitamins B6, B12, and folic acid is not suitable for the prevention of cerebral ischemias. A closer look at the cited studies yields interesting considerations and gives a different impression.
The VISP study was critically re-analyzed by the authors. After accounting for vitamin B12 malabsorption as the logical cause of the ineffectiveness of folic acid, the results were corrected and the relative risk for cerebral ischemia in this high-risk cohort was lowered by 18% by administration of vitamins (1).
The HOPE study also showed the effectiveness of homocysteine lowering vitamins in secondary prevention, demonstrating a 24% lower relative risk of cerebral ischemia (p = 0.03). It remains incomprehensible that the authors rate their only significant study result as incidental and irrelevant. The relevant figure was presented only as an appendix in the electronic version of the study (http://content.nejm.org/cgi/data/NEJMoa060900/DC1/1), but not in the printed version (2).
The new analysis of the NORVIT data by independent statisticians has shown favorable effects for the administration of vitamins for all clinical end points (3).
Necessary questions about the duration of treatment, dosages, and drug interactions were not considered in the studies mentioned.
The participants to benefit most are those with raised homocysteine levels and 36 months duration of therapy, which already points to the necessity of target group selection and sufficiently long treatment duration. Most participants in VISP, HOPE, and NORVIT did not have relevant vitamin deficiencies that justified treatment primarily, and although these studies investigated high-risk patients for cardiovascular events, they did not investigate target groups for effective homocysteine lowering with folic acid and other B vitamins. DOI: 10.3238/arztebl.2008.0128c

Priv.-Doz. Dr. med. Stefan Lorenzl
Interdisziplinäres Zentrum für Palliativmedizin
Klinikum Grosshadern
Marchioninistr, 15
81377 München, Germany
Stefan.Lorenzl@med.uni-muenchen.de

Dr. med. Michael Linnebank
Neurologie
Universitäts Spital Zürich
Frauenklinikstr. 26
CH-8091 Zürich, Switzerland

Prof. Dr. med. Olaf Stanger
Herzchirurgie
Salzburger Landeskliniken
Müllner Hauptstr. 48
A-5020 Salzburg, Austria

Conflict of interest statement
The authors declare that no conflict of interest exists according to the guidelines of the International Committee of Medical Journal Editors.
 1.
Spence JD, Bang H, Chambless LE, Stampfer MJ: Vitamin intervention for stroke prevention trial: an efficacy analysis. Stroke 2005; 36: 2404–9.
2.
Lonn E, Yusuf S, Arnold MJ, Sheridan P, Pogue J, Micks M, et al.: Homocysteine lowering with folic acid and B-vitamins in vascular disease. N Engl J Med 2006; 354:1567–77
 3.
Wang X, Demirtas H, Xu X: Homocysteine, B-vitamins, and cardiovascular disease. N Engl J Med 2006; 355: 207–9
 1. Spence JD, Bang H, Chambless LE, Stampfer MJ: Vitamin intervention for stroke prevention trial: an efficacy analysis. Stroke 2005; 36: 2404–9.
2. Lonn E, Yusuf S, Arnold MJ, Sheridan P, Pogue J, Micks M, et al.: Homocysteine lowering with folic acid and B-vitamins in vascular disease. N Engl J Med 2006; 354:1567–77
 3. Wang X, Demirtas H, Xu X: Homocysteine, B-vitamins, and cardiovascular disease. N Engl J Med 2006; 355: 207–9

Info

Specialities