RBC transfusions among hemodialysis patients (1999-2010): influence of hemoglobin concentrations below 10 g/dL

Changes in anemia management over the past decade have produced downward shifts in hemoglobin concentrations. We aimed to examine the effect on use of red blood cell (RBC) transfusions.

Retrospective cohort study.

We identified point prevalent Medicare hemodialysis patients as of January 1 of each year (1999-2010) and categorized them based on 3-month (April to June) mean hemoglobin levels (<10 or ≥10 g/dL) in each year.

Hemoglobin patterns over time and clinical profiles based on achieved hemoglobin concentrations.

RBC transfusion use.

We used negative binomial modeling to examine the effect of hemoglobin level <10 g/dL on transfusion use, adjusting for case-mix differences.

Proportions of patients with mean hemoglobin levels <10 g/dL decreased from 10% (1999) to ~4% (2005), but began increasing after 2006 and reached 6% by 2010. Accounting for case-mix differences, transfusion rates remained relatively constant at approximately 7.9 per 100 person-months for patients with hemoglobin levels <10 g/dL and 2 per 100 person-months for patients with hemoglobin levels ≥10 g/dL. Patients with average hemoglobin levels <10 g/dL were more likely to receive transfusions (risk ratio, 2.2; 95% CI, 2.1-2.2) even after adjustment; the risk ratio doubled if hemoglobin levels remained <10 g/dL for 6 months (4.4; 95% CI, 3.7-5.2).

Limited in generalizability to patients with Medicare as primary payer; residual confounding from factors such as frailty and chronic inflammation cannot be excluded; categorizing patients based on an average of 3 outpatient hemoglobin measurements may introduce some misclassification.

Risk of transfusion increases substantially with hemoglobin concentrations <10 g/dL; risk appears to be independent of other clinical factors. If anemia management patterns shift toward lower hemoglobin concentrations, RBC transfusion use likely will increase in dialysis patients.