Kasama R, Koch T, Canals-Navas C, Pitone JM
Vitamin B6 and hemodialysis: the impact of high-flux/high-
efficiency dialysis and review of the literature
Am J Kidney Dis
(May) 27:680-686 1996

It is well accepted that patients on chronic dialysis need
supplementation with water-soluble vitamins, including the B-complex
vitamins. Serum levels of vitamins are dependent not only on their
intake and absorption but also on their clearance from the dialyzer.
However, there is very little information available regarding the
clearance of vitamins by high-flux dialyzers. Kasama et al. and his
group studied in vivo clearances of serum pyridoxal-5' phosphate
(PLP), the active metabolite of vitamin B-6, in patients receiving 10
mg per day of pyridoxine supplements for patients receiving standard
cuprophan dialyzers versus cellulose triacetate high-flux,
high-efficiency dialyzers. In this crossover study, patients received
the same dose of dialysis in both the standard dialysis arm and the
high-flux, high-efficiency arm (average Kt/V of 1.45), and their
average protein catabolic rates were also similar (0.95-1.0 g/kg/body
weight/day) in both study arms. However, pre-dialysis vitamin B-6
levels decreased from 53 ng/mL in patients on standard dialysis to 24
ng/mL after receiving 3 months of high-flux, high-efficiency dialysis.
In addition, a marked increase in PLP clearance was noted from 86
mls/minute on standard dialysis up to 173 mls/minute on high-flux,
high-efficiency dialysis. In 4 of the 6 patients who then crossed
back to standard dialysis, their serum levels again increased back
into the normal range after receiving standard dialysis for at least 3
months
Comment: This study is the first study to rigorously assess the
impact of high-flux dialysis on serum vitamin levels. Undoubtedly,
other water-soluble vitamins are also cleared more efficiently on
high-flux dialysis than on standard dialysis. Additional research
will be needed to determine the appropriate supplementation of
water-soluble vitamins in patients who are receiving high-flux
hemodialysis.
Michael V. Rocco, M.D., Bowman Gray School of Medicine