Hemoglobin level variability in renal transplant patients treated with erythropoiesis stimulating agents

Treatment with erythropoiesis stimulating agents (ESA) is associated with fluctuations in hemoglobin (Hb) levels. Recently, variability of Hb has been considered a factor that influences comorbidity and mortality among hemodialysis patients. The purpose of this analysis was to describe the phenomenon of Hb variability during ESA treatment, to study associated factors among kidney transplant patients, and to assess the impact on patient and graft survivals.

Hb variability (defined as fluctuations of Hb +/- 1.5 g/dL) was assessed in 85 renal transplant patients treated with ESA for at least 3 months and with a minimum of 6 Hb measurements during 1 year.

Fifty-eight percent of the patients experienced Hb variability during follow-up. Only 3% of patients maintained stable Hb levels within the target range (11-13 g/dL), although 83% of patients maintained Hb levels >11 g/dL. Multivariate analysis showed that the clinical factors associated with variability were changes in ESA dose (relative risk [RR]: 2.92; 95% confidence interval [CI]: 1.0-8.5; P < .05), infectious events with hospitalization (RR: 1.95; 95% CI: 1.23-2.13; P < .05), and the use of sirolimus (RR: 1.1; 95% CI: 1.0-3.6; P < .05). When dose changes and hospitalization were excluded from the analysis, variability was an independent predictor of worsening graft function.

Hb variability is common in renal transplant patients treated with ESA. Only a few patients maintained Hb levels within the therapeutic range, although most had levels >11g/dL. Dose changes, inflammatory status, and worsening graft function are the determining factors of variability. Variability had no influence on patient survival, although it was a marker of worsening graft function.