Original Investigation
Dialysis
Facility-Level Interpatient Hemoglobin Variability in Hemodialysis Centers Participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS): Associations With Mortality, Patient Characteristics, and Facility Practices

https://doi.org/10.1053/j.ajkd.2010.11.003Get rights and content

Background

Hemodialysis patients with larger hemoglobin level fluctuations have higher mortality rates. We describe facility-level interpatient hemoglobin variability, its relation to patient mortality, and factors associated with facility-level hemoglobin variability or achieving hemoglobin levels of 10.5-12.0 g/dL. Facility-level hemoglobin variability may reflect within-patient hemoglobin variability and facility-level anemia-control practices.

Setting & Participants

Data from the Dialysis Outcomes and Practice Patterns Study (DOPPS; 26,510 hemodialysis patients, 930 facilities, 12 countries, 1996-2008) and from the Centers for Medicare & Medicaid Services (CMS; 193,291 hemodialysis patients, 3,741 US facilities, 2002).

Predictors

Standard deviation (SD) in single-measurement hemoglobin levels in hemodialysis patients in facility cross-sections (facility-level hemoglobin SD); patient characteristics; facility practices.

Outcomes

Patient-level mortality; additionally, facility practices correlated with facility-level hemoglobin SD or patient hemoglobin levels of 10.5-12.0 g/dL.

Results

Facility-level hemoglobin SD varied more than 5-fold across DOPPS facilities (range, 0.5-2.7 g/dL; mean, 1.3 g/dL) and by country (range, 1.1 in Japan-DOPPS [2005/2006] to 1.7 g/dL in Spain-DOPPS [1998/1999]), with substantial decreases seen in many countries from 1998 to 2007. Facility-level hemoglobin SD was related inversely to patient age, but was associated minimally with more than 30 other patient characteristics and facility mean hemoglobin levels. Several anemia management practices were associated strongly with facility-level hemoglobin SD and having a hemoglobin level of 10.5-12.0 g/dL. When examined in CMS data, facility-level hemoglobin SD was positively associated with within-patient hemoglobin SD during the prior 6 months. Patient mortality rates were higher with greater facility-level hemoglobin SD (DOPPS: HR, 1.08 per 0.5-g/dL greater facility-level hemoglobin SD [95% CI, 1.02-1.15; P = 0.006]; CMS: HR, 1.16 per 0.5-g/dL greater facility-level hemoglobin SD [95% CI, 1.11-1.21; P < 0. 001]).

Limitations

Residual confounding.

Conclusions

Facility-level hemoglobin SD was associated strongly and positively with patient mortality, not tightly linked to numerous patient characteristics, but related strongly to facility anemia management practices. Facility-level hemoglobin variability may be modifiable and its optimization may improve hemodialysis patient survival.

Section snippets

Data Sources

Primary analyses were based on 26,510 randomly selected maintenance hemodialysis patients 18 years or older from DOPPS I (1996-2001), II (2002-2004), and III (2005-2008) who had end-stage renal disease at least 180 days before study entry. Patients receiving dialysis for fewer than 180 days were excluded from our analyses to allow stabilization of patient hemoglobin during the first 6 months of hemodialysis therapy.16, 17 DOPPS is a prospective cohort study including nationally representative

Variation in Facility-Level Hemoglobin SD

Facility-level hemoglobin SD varied more than 5-fold across facilities (range, 0.51-2.72 g/dL; median, 1.27 g/dL; Fig 1). A nearly identical distribution in facility-level hemoglobin SD was seen when restricting to facilities reporting hemoglobin values for 15 or more patients or excluding patients hospitalized in the 3 months before calculation of facility-level hemoglobin SD. Facility-level hemoglobin SD was only marginally higher in facilities with higher mean hemoglobin (+0.022 g/dL per

Discussion

These results show substantially higher mortality rates for hemodialysis patients dialyzing in facilities with larger interpatient hemoglobin variation, defined as the SD in hemoglobin values in patients within a cross-section of facility hemodialysis patients. Overall, an 8% higher mortality rate was observed for every 0.5-g/dL greater facility-level hemoglobin SD in DOPPS after adjustment for numerous patient characteristics and facility practices. These findings essentially were unchanged by

Acknowledgements

We acknowledge the great efforts and contributions of the study nurses, physicians, medical directors, and patients from the more than 300 dialysis units that participated in each phase of the DOPPS; helpful comments and suggestions of Dr Eric J. Will, St James's University Hospital, Leeds, UK, during manuscript preparation; Jennifer McCready-Maynes for editorial assistance; and the CMS for the authorized use of CMS data for this investigation. Preliminary reports of some of this work have been

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