High platelet-to-red blood cell ratio and outcomes in trauma patients requiring massive transfusions

Abstract

Uncontrolled bleeding contributes to 40% of trauma deaths. While higher platelet-to-red blood cell (PLT/RBC) transfusion ratios may improve outcomes, the optimal ratio remains unclear. This study aimed to determine the threshold of PLT/RBC ratio and its impact on in-hospital mortality in trauma patients requiring massive transfusions. This retrospective, multicenter study used 2014–2018 National Trauma Database (NTDB) data. Adult patients admitted to Level I/II trauma centers with massive transfusions within 24 h of emergency department (ED) admission were included. Patients were divided into high-PLT group (PLT/RBC ratio > 0.7) and low-PLT group (ratio ≤ 0.7). Primary outcomes: 24-hour and 30-day mortality; secondary outcomes: transfusion-related adverse events. Among 9,330 patients (median age 37 (26–54) years; 78.9% male), 46.1% had a high PLT/RBC ratio. Restricted cubic spline analysis revealed a nonlinear relationship: mortality dropped significantly at > 0.7 and stabilized above 1.5. After inverse probability treatment weighting, the high-PLT group showed lower 24-hour mortality (OR, 0.45; 95% CI, 0.42–0.48) and 30-day mortality (OR, 0.66; 95% CI, 0.62–0.70). However, the high ratio group experienced higher rates of adverse events, including pulmonary embolism, acute kidney injury, and sepsis. Subgroup analyses confirmed consistent survival benefits despite increased adverse events. Sensitivity analysis further supported the robustness of these findings. In this multicenter study, a high PLT/RBC ratio (> 0.7) was associated with improved survival in trauma patients requiring massive transfusions, reducing 24-hour and 30-day mortality. However, it also increased the risk of adverse events, with a ceiling effect observed at ratios above 1.5. These findings underscore the need for high-quality clinical trials to validate the benefits of high PLT/RBC ratios and optimize transfusion strategies for trauma patients.