Homocysteine Lowering and Cognition in CKD: The Veterans Affairs Homocysteine Study
Brady, C.B., Gaziano, J.M. Czypoliski, R.A., Guarino, P.D., Kaufman, J.S., Warren, S.R., Hartigan, P., Goldfarb, D.S. and Jamison, R.L.
Objectives: The study was designed to investigate the relationship of the high homocysteine levels associated with chronic kidney disease and decreased cognitive function. Potential treatment by supplementation with high dose Vitamin B was investigated as well.
Methods: A randomized, double blind controlled study was conducted with 659 patients (mean age, 67.3 +/- 11.7 years) diagnosed with chronic kidney disease (CKD) or end-stage renal disease (ESRD) with coexisting high plasma total homocysteine levels (≥15μmol/L). Cognitive assessment by Telephone Interview of Cognitive Status-modified (TICSm) and supplemented with attention, working memory and executive function tests was initiated after implementation of Vitamin B treatment. The treatment consisted of either a daily high dose Vitamin B capsule (40 mg of folic acid, 100 mg of vitamin B6 , and 2 mg of vitamin B12) or placebo.
Results: Approximately 19% of patients had some level of cognitive impairment at the onset of the assessment, regardless of treatment assignment (vitamin or placebo) or kidney disease status. The treatment with high dose Vitamin B resulted in a decrease of tHcy levels by 26.7%. 1 year analysis (adjusted and unadjusted) showed no improvement in cognitive outcomes with treatment.
Conclusions: Cognitive outcomes were not affected significantly by treatment with high dose Vitamin B. A major limitation of this study was that cognitive assessment was begun after vitamin treatment was instituted. High dose daily Vitamin B supplementation was positively correlated with decreased tHcy levels.