Background: Erythropoiesis-stimulating agent (ESA) treatment is the optimal therapy for anemia in end-stage renal disease (ESRD) patients receiving hemodialysis. During treatment with ESA, the level of hemoglobin usually fluctuates widely; this phenomenon is known as “hemoglobin cycling” and may be associated with higher rates of mortality.
Objective: To estimate the prevalence of hemoglobin cycling in Thai ESRD patients treated with chronic maintenance
hemodialysis and ESA, to assess its clinical impact on patient outcomes, and to identify the associated risk factors for hemoglobin cycling occurrence.
Material and Method: An analytic retrospective study was conducted of 150 patients on chronic hemodialysis who were
treated with ESA at Rajavithi Hospital and the Kidney Foundation of Thailand at Priest’s Hospital between January 2008 and December 2010. Hemoglobin cycling was defined as hemoglobin variability over a period of at least 8 weeks and amplitude of more than 1.5 g/dl.
Results: Hemoglobin cycling was experienced by 90.7% of patients. The mean amplitude was 2.4+0.7 g/dl and mean duration of hemoglobin cycling was 8.5+5.0 weeks. Most patients (34.7%) experienced two episodes. The mean level of hemoglobin in patients with hemoglobin cycling (gr. I) and those without it (gr. II) were 10.1+0.9 g/dl and 10.2+0.7 g/dl respectively (p = 0.60). The mortality and hospitalization rates in gr. I and II were not significantly different (OR = 2.52; 95% CI: 0.31-20.27, p = 0.70 and OR = 1.65; 95% CI: 0.43-6.18, p = 0.56 respectively), and the numbers of ESA dose adjustments in gr. I and gr. II were also not significantly different (7.2+2.4 vs. 8.2+1.7 dose change/patient/year, p = 0.14). The serum levels of blood urea nitrogen, creatinine, intact parathyroid hormone, ferritin, % transferrin saturation, weekly Kt/Vurea and co-morbidity (diabetes mellitus, congestive heart failure, cerebrovascular disease and hypertension) were not significantly different in the two groups of patients.
Conclusion: Hemoglobin cycling was commonly found in Thai ESRD patients treated with hemodialysis and ESA. The influence of hemoglobin cycling on mortality and hospitalization rates could not be significantly demonstrated in the present study; however, both mortality and hospitalization rates showed an upward trend in patients with hemoglobin cycling.

Keywords: Anemia, Erythropoiesis-stimulating agent, Hemoglobin cycling, Hemodialysis