Background: Attempts to achieve near-normal hemoglobin levels have been associated with higher mortality among chronic kidney disease patients. Evidence suggests a higher mortality rate for those with resistance to erythropoietin-stimulating agents (ESA). We investigated the association between responsiveness to ESA, dose of ESA and mortality in our hemodialysis population. Methods: A retrospective cohort study of chronic hemodialysis patients receiving dialysis was conducted at the University of Virginia facilities. We collected data on patient demographics, comorbidities, dialysis vintage, vascular access type, body weight, ESA dose and hemoglobin, as well as data on known risk factors for ESA hyporesponsiveness. Vital status was determined 30 months later. The association between ESA responsiveness and mortality was investigated by using the Cox proportional hazard model adjusting for demographics, comorbidities, access type, dialysis adequacy, serum albumin, serum parathyroid hormone and ferritin concentrations. Results: A total of 606 patients were included. The overall 30-month mortality was 35.8%. Compared to those in the lowest tertile of ESA hyporesponsiveness, patients in the middle and upper tertiles had significantly higher mortality (hazard ratio, HR: 1.64, 95% CI: 1.14-2.37, and HR: 2.08, 95% CI: 1.46-2.97, respectively). In the Cox proportional hazard model each unit increment in the ESA resistance index was associated with an HR of 2.27 (95% CI: 1.60-3.23) for mortality. In this model each 1-unit increment in ESA dose/kg or each 100-μg increment in absolute darbepoetin alfa dose were associated with a 9% increased risk of mortality (HR: 1.09, 95% CI: 1.04-1.13, and HR: 1.09, 95% CI: 1.03-1.15, respectively). Conclusions: Among prevalent hemodialysis patients, a higher degree of resistance to and higher doses of ESA are associated with increased mortality.

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