Sex-based disparities in low-titer O whole blood utilization and mortality among severely injured trauma patients

Abstract

Background: Low-titer O whole blood (LTOWB) is commonly used in the United States for severe bleeding. Our objective was to examine disparities in LTOWB utilization and its association with survival. Study Design and Methods: This retrospective analysis included patients receiving at least 1 L of red blood cells (RBC) or LTOWB in the first 4 h of admission. Analyses were stratified by sex and age (<50 years “younger” and ≥50 years “older”). Adjusted analyses for the receipt of LTOWB and 24-h mortality were performed. Causal mediation analysis assessed whether the ratio of LTOWB to total transfused volume mediated associations with mortality. Results: The younger cohort included 21,192 females and 75,517 males, and the older cohort included 19,761 females and 40,924 males. Upon adjusted analyses, younger and older females were less likely to receive LTOWB OR (95% confidence interval [CI]), 0.61 (0.58–0.64) and OR 0.83 (0.76–0.87), respectively. Increased ratio of LTOWB to total transfused volume was independently associated with reduced mortality in males and females in both young and older cohorts, OR 0.81 (0.74–0.89) and OR 0.74 (0.66–0.83), respectively. Older females had an increased risk of mortality compared with males, OR 1.18 (1.09–1.28). Causal mediation analysis indicated a negligible influence of LTOWB:TTV ratio on the associations between patient sex and mortality (0.11% younger; 0.02% older cohorts). Conclusion: Significant sex-based disparities exist in LTOWB utilization among severely injured trauma patients. Higher LTOWB ratios are associated with reduced mortality in both females and males. Females above 50 are at increased risk of mortality unrelated to the LTOWB ratio administered.