Relationship between hemoglobin variability and prognosis in dialysis patients

Objective To investigate the epidemiological characteristics of hemoglobin variability (Hb-Var) in dialysis patients, and to explore the factors related to Hb-Var and the relationship between Hb-Var and patients outcomes. Methods The study enrolled 178 hemodialysis and peritoneal dialysis patients in the Department of Nephrology, Peking University People's Hospital between October 2009 and March 2010. First six months were observation period, and then followed up for 12 months. The Hb-Var was described by residual standard deviation (Res-SD) and fluctuation across threshold of the Hb level. Non-fatal cardiovascular events and mortality were the primary endpoints. Results The Res-SD was (4.74±2.66) g/L in dialysis patients. Most patients fell into groups of high amplitude (HA) and low amplitude low (LAL), with frequency of 29.8% and 33.1% respectively. The related factors of Hb-Var were fluctuation of erythropoietin (EPO) dosage and hemodialysis. Kaplan-Meier survival curve and multivariable adjusted Cox regression indicated that Res-SD had no impact on the primary endpoints. Accumulative time to reach target hemoglobin level was an independent factor related to outcome. Conclusion Hb-Var occurs commonly in dialysis patients. The fluctuation of EPO dosage and dialysis style increase Hb-Var. Accumulative time to reach target hemoglobin level is an independent factor related to patients outcomes.