Timing and sex bias in prehospital prediction of trauma transfusion requirements

We read with interest the Prehospital Transfusion Score (PTS) proposed by Pérez-García et al.,1 which demonstrated excellent discrimination in predicting emergency and massive transfusion among patients with major trauma. However, several methodological aspects remain underexplored and warrant further consideration. First, sex-based differences were evident but not integrated into the model. Although women comprised roughly one quarter of the cohort, they accounted for nearly 40% of massive transfusion cases.1 Previous studies have shown that female trauma patients often experience delays in resuscitation, display distinct coagulation profiles, and are managed using different transfusion thresholds, suggesting that fixed physiological cut-offs may not perform equivalently between the sexes.2–4 The absence of sex-adjusted calibration may therefore compromise predictive accuracy and equity in women. Second, timing confounding constitutes an important methodological limitation. Patients requiring transfusion experienced longer on-scene times,1 resulting in greater metabolic deterioration before point-of-care testing. Because lactate, base deficit, and pH are highly time-sensitive variables, delayed sampling may have overstated the apparent discrimination of the PTS, making its performance partly dependent on elapsed time rather than the true severity of haemorrhage.5 Adjusting for prehospital delay is therefore essential, particularly in systems with variable evacuation intervals.