Original Investigation
Dialysis
Anemia Management and Association of Race With Mortality and Hospitalization in a Large Not-for-Profit Dialysis Organization

https://doi.org/10.1053/j.ajkd.2009.05.007Get rights and content

Background

The optimal hemoglobin target and possible toxicity of epoetin therapy in hemodialysis patients are controversial. Previous studies suggest that African American patients use higher doses of epoetin and have better survival compared with white hemodialysis patients.

Study Design

Retrospective longitudinal cohort.

Setting & Participants

Epoetin-exposed incident hemodialysis patients (N = 12,733; African Americans, n = 4,801; white, n = 7,386) treated in Dialysis Clinic Inc facilities during 2000 to 2006.

Predictors

Hemoglobin, epoetin, iron.

Outcomes

Mortality, hospitalization.

Measurements

Proportional hazards models with time-varying covariates.

Results

Hemoglobin concentrations less than 10 g/dL in whites and less than 11 g/dL in African Americans were associated with increased mortality and hospitalization versus the referent hemoglobin level of 11 to 11.9 g/dL. Hemoglobin levels of 13 g/dL or greater in whites were associated with decreased noncardiovascular mortality. Six-month cumulative epoetin doses of 20,000 U/wk or greater were associated with increased mortality and hospitalization versus the referent group (8,000 to 12,499 U/wk). Epoetin doses less than 8,000 U/wk were associated with decreased risk. Higher epoetin doses were associated with increased mortality at hemoglobin concentrations of 10 to 12.9 g/dL and with increased hospitalization at all hemoglobin concentrations of 10 g/dL or greater. Higher epoetin doses were associated with increased mortality and hospitalization within each tertile of serum albumin concentration. These patterns did not differ by race.

Limitations

Treatment-by-indication bias and unidentified confounders cannot be excluded. Small sample sizes in the highest and lowest hemoglobin strata decrease statistical power.

Conclusions

Relationships between hemoglobin concentration and mortality differed between African Americans and whites. Additionally, the relationship of lower mortality with greater achieved hemoglobin concentration seen in white patients was observed for all-cause, but not cardiovascular, mortality. A higher cumulative epoetin dose was associated with worse outcomes, even in patients with albumin levels greater than 4 g/dL. There were no statistically significant interactions between race and epoetin dose. Further studies are needed to confirm and to define the mechanism of these findings.

Section snippets

Study Participants

We studied an incident cohort that began hemodialysis therapy at a Dialysis Clinic Inc (DCI) facility between January 1, 2000, and December 31, 2006. Inclusion criteria included age of 20 years or older at the diagnosis of end-stage renal disease (ESRD) and survival of 1 year or longer from the first outpatient hemodialysis treatment. We restricted the cohort to patients with 1 year or more of follow-up to allow sufficient time for epoetin dose to stabilize. Follow-up for death or

Results

Of 22,693 patients 20 years or older who initiated hemodialysis therapy at DCI during 2000 to 2006, a total of 12,733 survived and were followed up for at least 365 days. Demographics of the study sample were similar to the US Renal Data System (USRDS) hemodialysis cohort in 2002 (Table 1), except that African Americans were slightly overrepresented.29 Median follow-up beyond the required 365 days was 522 days (range, 1 to 2,556 days). At the start of follow-up, 6.5% of patients had a

Discussion

The present study is in concert with other reports showing the associations of decreased mortality with greater hemoglobin concentration5, 6 and increased mortality with high epoetin dose in hemodialysis patients.7 We extended these previous observations by showing: (1) a similar association with hospitalization; (2) an association between greater epoetin dose with mortality and hospitalization, even in patients with a serum albumin level greater than 4 g/dL; (3) that the relationship of

Acknowledgements

The authors thank DCI for their generous support; the patients of DCI, without whom this would not have been possible; and Christopher Adams, MD, Serena Cumber, Kelly Utterback, and Candice Welhausen for technical and professional help.

Support: Drs Singh, Miskulin, Meyer, and Zager receive support from DCI through their respective institutions.

Financial Disclosure: None.

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    Originally published online as doi: 10.1053/j.ajkd.2009.05.007 on July 24, 2009.

    Because the Editor-in-Chief and Deputy Editor recused themselves from consideration of this manuscript, the peer-review and decision-making processes were handled entirely by a Co-Editor (James S. Kaufman, MD, Renal Section, Veterans Affairs Boston Healthcare System and Boston University School of Medicine, Boston, MA) who served as Acting Editor-in-Chief. Details of the journal's procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.

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    Copyright © 2009 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.