Abstract / Summary
Abstract Background: Early prognostic assessment in trauma remains challenging, and readily available biomarkers that complement established severity and perfusion-based measures are of considerable clinical interest. Red cell distribution width (RDW), an inexpensive parameter routinely reported in the complete blood count, has emerged as a potential prognostic marker in acute illness, but its relevance in trauma resuscitation remains uncertain. We aimed to evaluate the association between admission RDW and in-hospital mortality in trauma patients treated in a level I resuscitation room and explored its relationship with macrocirculatory and hyperspectral imaging (HSI)-derived microcirculatory parameters.
Methods: This secondary analysis of a prospective single-centre observational cohort included 165 trauma patients admitted to a level I trauma resuscitation room. The primary exposure was admission RDW, and the primary outcome was in-hospital mortality. Logistic regression was used to evaluate the association between RDW and mortality, adjusted for injury severity score (ISS) and age in the primary multivariable model. Sensitivity analyses additionally adjusted for haemoglobin and applied Firth’s penalised logistic regression. Secondary analyses examined associations between RDW and baseline macrohaemodynamic variables, serum lactate, and HSI-derived microcirculatory indices using ISS-adjusted linear regression with robust standard errors. Discriminative performance for mortality was assessed by receiver operating characteristic analysis.
Results: In-hospital mortality was 11.0%. Mean admission RDW was 13.1% (SD 0.97). RDW was strongly associated with in-hospital mortality in unadjusted analysis (OR 2.85 per 1% increase, 95% CI 1.71–4.73; p < 0.001). In the primary model adjusted for ISS and age, effect magnitude remained similar, although statistical significance was attenuated (OR 2.09, 95% CI 0.98–4.45; p = 0.056). Additional haemoglobin adjustment and Firth correction yielded comparable estimates. RDW was not independently associated with baseline mean arterial pressure, shock index, capillary refill time, lactate, or HSI-derived microcirculatory indices. RDW showed good discriminatory performance for mortality (AUC 0.845, 95% CI 0.765–0.925).
Conclusion: Admission RDW was associated with in-hospital mortality in this trauma cohort, with a stable effect size after adjustment for injury severity and age. Its prognostic signal was not explained by measurable baseline macro- or microcirculatory impairment, suggesting that RDW may capture broader biological vulnerability beyond conventional early perfusion assessment. Trial registration German Clinical Trials Register (DRKS ID DRKS00030986) on 27 December 2022