Red blood cell survival in chronic renal failure.

BACKGROUND

A decrease in the lifespan of erythrocytes has been accepted universally as one of the contributory factors to anemia in patients with chronic renal failure. This observation was made in the 1950s and 1960s when continuous renal replacement therapy was at its infancy. Based on the premise that a reduced red blood cell (RBC) lifespan in renal disease is primarily caused by the toxic uremic milieu, the purpose of this study is 2-fold: to compare the RBC survival in today's renal patients with that in the existing literature and to explore if there are differential RBC survival benefits with various dialysis dosages.

METHODS

This is an observational study. Patients with end-stage renal disease were recruited from the dialysis program at the University Health Network and St Michael's Hospital in Toronto. The patients were stratified into 3 groups including conventional thrice-weekly, nocturnal, and short-daily hemodialysis. Healthy subjects were recruited to validate the normal range for RBC lifespan. Red cell survival was assessed using radiolabeled sodium chromate (Na2 51CrO4).

RESULTS

Twenty-two patients and 2 healthy control subjects were recruited. The average red cell half-lives in thrice-weekly, nocturnal, short-daily, and healthy subjects were 14.5 +/- 1.6, 17.1 +/- 4.7, 15.9 +/- 2.2, and 23.5 days, respectively. All 3 patient groups exhibited reduced RBC lifespan (P < 0.05). Further, the overall RBC lifespan was not different from that reported half a century ago. Despite better urea clearances among the nocturnal and short-daily dialysis groups, no RBC survival benefit was observed.

CONCLUSION

A reduced RBC lifespan continues to contribute to renal anemia despite technologic advancements and improved uremic environment.