Is vitamin B(6) deficiency an under-recognized risk in patients receiving haemodialysis? A systematic review: 2000-2010.

Vitamin B6 is a water-soluble vitamin, important for the normal functioning of multiple organ systems. In patients receiving haemodialysis, vitamin B6 deficiency has been reported. The impact of ongoing advances in renal medicine on vitamin B6 status has not been evaluated. The aims of this review were (i) to determine the current level of vitamin B(6) deficiency in the haemodialysis population; (ii) to determine the effect of current haemodialysis prescriptions on vitamin B(6) levels; and (iii) to consider the impact of recent medical advances in haemodialysis on vitamin B(6) levels. Electronic databases were used to locate studies with biochemical measures of vitamin B6 between the years 2000 and 2010. Inclusion exclusion criteria were applied by two independent reviewers. Of 316 articles identified, 53 were selected for detailed review. Appropriate vitamin B6 measures and information were extracted. Eleven final studies were included. Vitamin B6 deficiency was shown to be between 24% and 56%. Dialysis reduced plasma levels by 28-48% depending on the dialyser used. Advances in renal medicine including the use of erythropoietin stimulating agents and ion exchange phosphate binding resins were shown to negatively affect vitamin B6 status. Current recommendations for supplementation range from 10-50 mg. These figures are based on older studies often with small numbers of patients. Suboptimal vitamin B6 status is common in the haemodialysis population. Advances in renal medicine and engineering of dialysis membranes may contribute to increased levels of deficiency.