Geographic variation in blood transfusion among <scp>TRICARE</scp> beneficiaries

BACKGROUND: Blood is a critical but inconsistently distributed resource. Within the United States, there are known state-level variations in blood product distribution; however, little is known about geographic variations in transfusion practices on a national level. The US Military Health System offers an opportunity to study a nationally representative population through the TRICARE insurance claims database. STUDY DESIGN AND METHODS: Claims from beneficiaries with acute bleeding diagnoses (related to trauma, postpartum hemorrhage, or gastrointestinal bleeding) from 2017 to 2022 were analyzed. Multivariable logistic regressions were used to examine relationships between geographic characteristics (hospital region and rurality) and transfusion status. RESULTS: The study population consisted of 87,034 admissions. In adjusted models, rural trauma patients were significantly less likely to be transfused than urban trauma patients (aOR 0.18, 0.03-0.55). Conversely, rural postpartum hemorrhage and gastrointestinal bleeding patients were more likely to be transfused than their urban counterparts (aOR 1.63, 1.32-2.00 and aOR 1.24, 1.11-1.37, respectively). Hospital region was significantly associated with transfusion status among the postpartum hemorrhage and gastrointestinal bleeding cohorts, with patients in the Midwest less likely to receive a transfusion than patients in the Northeast (aOR 0.33, 0.24-0.45 and aOR 0.60, 0.52-0.70, respectively). DISCUSSION: In this sample, geographic factors including hospital region and rurality were independently associated with transfusion status among inpatients with acute bleeding diagnoses. These variations may reflect provider- or system-level factors and can help identify areas of potential vulnerability.