Change in use of allogeneic red blood cell transfusions among surgical patients.

BACKGROUND: Although RBC transfusions can be lifesaving, recent evidence suggests that their use is associated with added morbidity and mortality and that a lower transfusion threshold is safe. It is unclear if this new evidence has translated into decreased RBC use among surgical patients. The purpose of this study is to measure the change in use of RBCs during the last decade. STUDY
DESIGN: We performed a cross-sectional cohort study of all patients who underwent inpatient operations in the 52 hospitals in Maryland in 1997 to 1998 and 2004 to 2005. The primary outcomes variable was whether or not the patient received an allogeneic RBC transfusion. We controlled for confounders related to RBC transfusion, including age, gender, race, type of admission, comorbid conditions, and surgeon patient-volume.
RESULTS: Patients receiving RBCs were older (63 versus 52 years), were more likely to be admitted through the emergency department (37% versus 24%) or as a readmission (12% versus 6.9%), had more Romano-Charlson index comorbidities, and had a higher unadjusted mortality (6.5% versus 1.1%). Comparing 1997 to 1998 to 2004 to 2005, RBC use in surgical patients increased (8.9% versus 14%), although unadjusted mortality decreased (2.0% versus 1.5%). Factors associated with higher adjusted relative risk (RR) of transfusion include age older than 65 years (RR = 2.45), unscheduled admissions (emergency department RR = 1.32, readmission RR = 1.62), Romano-Charlson comorbidities (RR = 1.04 to 2.71), third quartile of surgeon volume (RR = 1.10), death (RR = 1.24), and having operations in 2004 to 2005 (RR = 1.42).
CONCLUSIONS: Despite evidence supporting more restrictive use of RBC transfusions, RBC use among surgical patients has increased during the last decade.