BACKGROUND: Transfusion-related acute lung injury (TRALI) and hemolytic transfusion reactions account for significant transfusion-related morbidity and mortality in the United States. Our study evaluated types and quantities of transfused components as well as occurrence of TRALI, ABO, and Rh incompatibilities among the US elderly in the institutional outpatient setting during 2007 to 2008.

STUDY DESIGN AND METHODS: This retrospective claims-based study utilized the Centers for Medicare & Medicaid Services' large administrative databases. Transfusions were identified by recorded procedure and revenue center codes, while complications were ascertained via ICD-9-CM diagnosis codes. The study quantified blood use based on revenue center units.

RESULTS: Among 26,054,242 and 25,662,864 Medicare elderly in 2007 and 2008, a total of 241,055 (0.9%) and 251,284 (1.0%) had outpatient transfusions. Leukoreduced red blood cells (LR-RBCs) was the most frequently transfused single blood component (60.1 and 61.3%, respectively) each year. Likewise, LR-RBCs and LR pheresis platelets (LR-PLTs) was the most frequent component combination (2.4 and 2.6%, respectively). TRALI rate comparison for RBCs and PLTs versus RBCs only showed higher rate for RBCs and PLTs (p = 0.033). In 2007 and 2008, ABO incompatibility rate comparison for irradiated (IR) LR-RBCs versus LR-RBCs showed higher rates for IR LR-RBCs (rate ratio [RR] 37.4, 95% confidence interval [CI] 10.6-132.6; and RR 31.3, 95% CI 11.6-84.4, respectively).

CONCLUSION: This study shows potential usefulness of Medicare databases in assessment of blood utilization, transfusion-related complications, and risk factors among US elderly in the outpatient setting. It suggests limitations (e.g., need for several years of data to better assess rare complications) and importance of databases as hypothesis-generating tool to supplement blood safety research.