The Neutrophil-to-Albumin Ratio as an Independent Prognostic Biomarker for 28-Day Mortality in Trauma-Induced Acute Respiratory Distress Syndrome: A Retrospective Cohort Study With External Validation.

Authors

Ziming Huang, Yuze Jia, Zifan Chen

Published in

Respiratory medicine. Pages 109156. Sep 19, 2026. Epub Sep 19, 2026.

Abstract

Acute respiratory distress syndrome (ARDS) secondary to trauma remains associated with high in-hospital mortality, and there is an unmet need for accessible, cost-effective biomarkers to stratify mortality risk in this patient population. The neutrophil-to-albumin ratio (NAR), a composite inflammatory-nutritional biomarker, has shown prognostic value in multiple critical illness cohorts but has not been systematically evaluated in trauma-induced ARDS.
This study aimed to assess the predictive performance of NAR for 28-day mortality in patients with trauma-induced ARDS, using a large public critical care database followed by external validation in a single-center intensive care unit (ICU) cohort, to establish NAR as a practical tool for risk stratification in acute trauma care.
This retrospective cohort study extracted data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. NAR was calculated using serum neutrophil count and albumin level measured at the first measurement following the diagnosis of trauma-induced ARDS. The optimal cut-off value for NAR was determined using the Youden index. Prognostic accuracy for 28-day mortality was evaluated via receiver operating characteristic (ROC) curve analysis. Multivariate Cox regression was used to identify independent predictors of mortality, and 11 prespecified subgroup analyses were performed to assess the consistency of NAR's prognostic performance across clinical strata. External validation was conducted in a cohort of 122 consecutive trauma-induced ARDS patients admitted to our regional trauma center ICU.
A total of 1494 patients with trauma-induced ARDS were included in the MIMIC-IV cohort, with a 28-day all-cause mortality rate of 23.4% (350 non-survivors, 1144 survivors). Multivariate Cox regression identified elevated NAR as an independent predictor of 28-day mortality (adjusted hazard ratio [HR] = 1.423, 95% confidence interval [CI] 1.233-1.776, P = 0.003). The optimal NAR cut-off value for mortality discrimination was 2.43. Kaplan-Meier survival analysis confirmed that patients with NAR ≥2.43 had significantly higher 28-day mortality than those with NAR <2.43 (log-rank test, P < 0.001). NAR achieved an area under the ROC curve (AUC) of 0.758 (95% CI 0.694-0.802), which was superior to the predictive performance of individual components: neutrophil count (AUC = 0.648) and albumin level (AUC = 0.643). Subgroup analyses demonstrated consistent prognostic value of NAR across all clinical strata (interaction P values 0.143-0.782). In the external validation cohort, elevated NAR remained independently associated with higher 28-day mortality (adjusted HR = 1.254, 95% CI 1.196-1.429, P < 0.001), with an AUC of 0.709 (95% CI 0.659-0.847).
NAR is an independent, robust predictor of 28-day mortality in patients with trauma-induced ARDS, with superior discriminative capacity compared to its individual components. This easily accessible biomarker may support early risk stratification and clinical decision-making in critically ill trauma patients.

PMID:
42763089
Bibliographic data and abstract were imported from PubMed on 20 Sep 2026.

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