Sex-based differences in transfusion need after severe injury: Findings of the PROPPR study

Abstract

Background: Women are underrepresented in trauma research, and aggregated results of clinical trials may mask effects that differ by sex. It is unclear whether women respond differently to severe hemorrhage compared with men. We sought to evaluate sex-based differences in outcomes after severe trauma with hemorrhage.

Methods: We performed a secondary analysis of the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Trauma patients predicted to require massive transfusion were randomized to a 1:1:1 vs 1:1:2 plasma to platelet to red blood cell transfusion ratio. Analysis was performed according to sex, controlling for clinical characteristics and transfusion arm.

Results: A total of 134 women and 546 men were analyzed. In multivariable analysis, there was no difference in mortality at 24 hours (hazard ratio for women 0.64, 95% confidence interval 0.34-1.23, P = .18) or in time to hemostasis (hazard ratio 1.10, 95% confidence interval 0.84-1.42, P = .49) by sex. We observed no difference between sexes in volume of blood products transfused during active hemorrhage. However, after anatomic hemostasis, women received lower volumes of all products, with a 38% reduction in fresh frozen plasma (mean ratio 0.62 (95% confidence interval 0.43-0.89, P = .01), 49% reduction in platelets (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01) and 49% reduction in volume of red blood cells (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01).

Conclusion: Mortality and time to hemostasis of trauma patients with hemorrhage did not differ by sex. Although there was no difference in transfusion requirement during active hemorrhage, once hemostasis was achieved, women received fewer units of all blood products than men. Further research is required to determine whether women exhibit differences in coagulation during and after severe traumatic hemorrhage.

Figure 1.. Mean units of blood products by sex and treatment arm for the post-hemostasis period

Figure 2a). Hazard Ratio for clinical outcomes: female sex

Model adjusted for age, sex, race, weight, height, mechanism of injury, base deficit, INR, AIS head, chest, abdomen, extremities, external, face and neck, and transfusion arm (1:1:1 vs 1:1:2)

Figure 2b). Mean Ratios for post-hemostasis period blood transfusion volume: female sex

Model adjusted for age, sex, race, weight, height, mechanism of injury, base deficit, INR, AIS head, chest, abdomen, extremities, external, face and neck, and transfusion arm (1:1:1 vs 1:1:2)