Comparative mortality risk of anemia management practices in incident hemodialysis patients

Abstract

Context: Controversy exists about optimal management of anemia in end-stage renal disease.

Objective: To compare the mortality risk of different dialysis center-level patterns of anemia management.

Design, setting, and patients: Using data from Medicare's end-stage renal disease program (1999-2007), we characterized each US dialysis center's annual anemia management practice by estimating its typical use of erythropoiesis-stimulating agents (ESAs) and intravenous iron in hemodialysis patients within 4 hematocrit categories. We used Cox proportional hazards regression to correlate center-level patterns of ESA and iron use with 1-year mortality risk in 269,717 incident hemodialysis patients.

Main outcome measure: One-year all-cause mortality.

Results: Monthly mortality rates were highest in patients with hematocrit less than 30% (mortality, 2.1%) and lowest for those with hematocrit of 36% or higher (mortality, 0.7%). After adjustment for baseline case-mix differences, dialysis centers that used larger ESA doses in patients with hematocrit less than 30% had lower mortality rates than centers that used smaller doses (highest vs lowest dose group: hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.90-0.97). Centers that administered iron more frequently to patients with hematocrit less than 33% also had lower mortality rates (highest vs lowest quintile, HR, 0.95; 95% CI, 0.91-0.98). However, centers that used larger ESA doses in patients with hematocrit between 33% and 35.9% had higher mortality rates (highest vs lowest quintile, HR, 1.07; 95% CI, 1.03-1.12). More intensive use of both ESAs and iron was associated with increased mortality risk in patients with hematocrit of 36% or higher. These findings persisted across a range of secondary analyses.

Conclusions: Greater ESA and iron use were associated with decreased mortality risk at lower hematocrit levels, in which mortality rates are the highest. Although the overall mortality rate was lower at higher hematocrit levels, elevated mortality risk was associated with greater use of ESAs and iron in these patients.