Temporal trends in red blood transfusion among US dialysis patients, 1992-2005

Abstract

Background: Studies addressing patterns and trends in red blood cell transfusion use in US hemodialysis patients surprisingly have received little attention in the last decade.

Study design: Retrospective cohort study.

Setting & participants: Point prevalent (as of January 1 of each calendar year 1992 to 2005) dialysis patients with Medicare Part A and Part B as primary insurance (n = 77,347 in 1992, n = 164,933 in 2005). The 6 months preceding January 1 of each year were used to assemble a comorbidity profile based on administrative claims data.

Predictors: Hemoglobin levels, patient characteristics, comorbid conditions.

Outcomes: Blood transfusion events obtained from Part A and Part B files using code files for both whole and packed red blood cell transfusions and hemoglobin levels.

Measurements: Comorbid conditions were defined by the presence of 1 or more inpatient/outpatient institutional claims (inpatient hospitalization, skilled nursing facility, or home health agency), 2 or more outpatient or physician/supplier claims, or 1 or more outpatient and 1 or more physician/supplier claims for atherosclerotic heart disease, congestive heart failure, cerebrovascular accidents/transient ischemic attacks, peripheral vascular disease, other cardiovascular diseases, chronic obstructive pulmonary disease, gastrointestinal disorders, liver disease, arrhythmia, and diabetes mellitus.

Results: Raw transfusion rates decreased in both outpatient and inpatient settings from 535.33/1,000 patient-years for 1992 prevalent dialysis patients to 263.65/1,000 patient-years in 2005 (P for trend < 0.001, 1992 versus 1999 and 1999 versus 2005). Adjusted rates decreased similarly. This phenomenon could not be explained by changes in case mix.

Limitations: Cause, effect, and confounding cannot be separated in this observational study. The accuracy of blood transfusion billing data is unknown. Temporal trends may be related to factors other than erythropoiesis-stimulating agent use.

Conclusion: Transfusion events in hemodialysis patients decreased more than 2-fold from 1992 to 2005; most of the decrease occurred in the first 5 years after erythropoietin was introduced.