Erythropoietin Resistance Index and the All-Cause Mortality of Chronic Hemodialysis Patients

Abstract

Background: Evidence suggests hemodialysis (HD) patients with resistance to erythropoiesis-stimulating agents (ESA) have a higher mortality rate. We investigated the association between ESA responsiveness and mortality in our HD population. Methods: A prospective cohort study of chronic HD patients was conducted at Jyoban Hospital in Fukushima, Japan. We collected data on patient demographic factors, comorbidities, dialysis vintage, body weight, ESA dose and hemoglobin concentration, as well as data on known risk factors for ESA hyporesponsiveness. The erythropoietin resistance index (ERI) was calculated by dividing the weekly body-weight-adjusted epoetin dose by the hemoglobin concentration. The association between ESA hyporesponsiveness estimated by the highest tertile of ERI and mortality was investigated by using the Cox proportional hazards model with adjustments for demographic factors, comorbidities, dialysis adequacy and serum biochemical data. Results: A total of 248 patients were included as subjects in the cohort, and their overall 2-year mortality rate was 13.3%. According to the results of the Kaplan-Meier analysis, patients with an ERI in the highest tertile had significantly higher mortality than patients with an ERI in the lower two tertiles (p = 0.0121). The highest ERI tertile was associated with higher all-cause mortality in both the unadjusted hazards model (hazard ratio, HR: 4.429; 95% CI: 1.249-15.704) and the adjusted hazards model (HR: 4.204; 95% CI: 1.173-15.065). Conclusions: A higher degree of resistance to ESA in chronic HD patients is associated with increased mortality.