Early hemoglobin trajectories and short-term mortality in ICU patients with traumatic brain injury: development in MIMIC-IV and external assessment in eICU-CRD.
- 1Department of Neurosurgery, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, China.
- 2Nanjing Medical University, Nanjing, China.
- 3Department of Infectious Diseases, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, China.
Abstract
Background
Hemoglobin (Hb) changes dynamically after traumatic brain injury (TBI), but the prognostic relevance of distinct longitudinal patterns and their added value beyond early Hb remain uncertain. We characterized early Hb trajectories in ICU patients with TBI and examined associations with mortality after a 120-h landmark.Methods
MIMIC-IV was used for model development and multicenter eICU-CRD for external assessment. Daily median Hb values across five 24-h windows were modeled using a latent class linear mixed model. The three-class MIMIC-IV model was frozen before transport to eICU. Cox models evaluated mortality from 120 h through ICU day 28, with sensitivity analyses addressing selection, landmark attrition, simpler Hb summaries, classification uncertainty, PRBC exposure, missingness, and nonproportional hazards.Results
In MIMIC-IV, 2,466 patients entered trajectory analysis and 2,409 entered post-landmark analysis. Three trajectories were identified: relatively high and stable, rapidly declining, and persistently low Hb. In fully adjusted models, rapidly declining (HR 1.74, 95% CI 1.18-2.57) and persistently low Hb (HR 1.57, 95% CI 1.19-2.08) were associated with higher mortality. In eICU, 2,097 patients were classified and 1,557 entered outcome analysis; persistently low Hb remained associated with mortality (HR 1.58, 95% CI 1.03-2.43), whereas the rapidly declining association was less precise (HR 1.24, 95% CI 0.80-1.92). Adding trajectory class to the MIMIC-IV clinical model increased the C-index from 0.786 to 0.792. After adjustment for first-day Hb, the rapidly declining trajectory remained associated with mortality (HR 1.77, 95% CI 1.20-2.62), whereas the persistently low association attenuated (HR 1.27, 95% CI 0.83-1.93). Independent three-class refitting in eICU did not recover the same latent-class structure (ARI 0.169).Conclusion
Early Hb trajectories after TBI showed distinct prognostic associations. Persistently low Hb had the most consistent transported association but was attenuated after first-day Hb adjustment; rapid decline retained an association in MIMIC-IV but had limited external support. Incremental discrimination was modest. These patterns should be interpreted as treatment-embedded clinical courses rather than fixed biological phenotypes or evidence for trajectory-specific transfusion thresholds.
Related
- Hemoglobin-to-red blood cell distribution width ratio and in-hospital mortality in patients with non-traumatic subarachnoid hemorrhage: a retrospective cohort study
- Hemoglobin glycation index and the dynamic progression of cardiometabolic multimorbidity and mortality: a multi-state Markov analysis
- The relationship between hemoglobin concentration and mortality in patients receiving venovenous extracorporeal membrane oxygenation support: a single-center retrospective cohort study
- Human hemoglobin protects the parasite cytoskeleton during Plasmodium falciparum gametocyte development
- Development and internal validation of an oxygen saturation-based prehospital cardiac risk assessment index (P-CRAI) for predicting 30-day mortality in acute myocardial infarction: a multicentre registry study from the Mie ACS Registry, Japan
BibTeX
@article{li2026early,
title = {{Early hemoglobin trajectories and short-term mortality in ICU patients with traumatic brain injury: development in MIMIC-IV and external assessment in eICU-CRD.}},
author = {Saijie Li and Yanyu Han and Feiyu Ding and Zhichao Qiu and Xuezi Ma and Hanyu Huang and Bin Zhang and Handong Wang},
journal = {Frontiers in neurology},
year = {2026},
month = oct,
doi = {10.3389/fneur.2026.1967355},
url = {https://europepmc.org/article/MED/42903095},
note = {CC BY},
}
RIS
TY - JOUR
TI - Early hemoglobin trajectories and short-term mortality in ICU patients with traumatic brain injury: development in MIMIC-IV and external assessment in eICU-CRD.
AU - Saijie Li
AU - Yanyu Han
AU - Feiyu Ding
AU - Zhichao Qiu
AU - Xuezi Ma
AU - Hanyu Huang
AU - Bin Zhang
AU - Handong Wang
PY - 2026
DA - 2026/10/06
JO - Frontiers in neurology
DO - 10.3389/fneur.2026.1967355
UR - https://europepmc.org/article/MED/42903095
AB - Background Hemoglobin (Hb) changes dynamically after traumatic brain injury (TBI), but the prognostic relevance of distinct longitudinal patterns and their added value beyond early Hb remain uncertain. We characterized early Hb trajectories in ICU patients with TBI and examined associations with mortality after a 120-h landmark.Methods MIMIC-IV was used for model development and multicenter eICU-CRD for external assessment. Daily median Hb values across five 24-h windows were modeled using a latent class linear mixed model. The three-class MIMIC-IV model was frozen before transport to eICU. Cox models evaluated mortality from 120 h through ICU day 28, with sensitivity analyses addressing selection, landmark attrition, simpler Hb summaries, classification uncertainty, PRBC exposure, missingness, and nonproportional hazards.Results In MIMIC-IV, 2,466 patients entered trajectory analysis and 2,409 entered post-landmark analysis. Three trajectories were identified: relatively high and stable, rapidly declining, and persistently low Hb. In fully adjusted models, rapidly declining (HR 1.74, 95% CI 1.18-2.57) and persistently low Hb (HR 1.57, 95% CI 1.19-2.08) were associated with higher mortality. In eICU, 2,097 patients were classified and 1,557 entered outcome analysis; persistently low Hb remained associated with mortality (HR 1.58, 95% CI 1.03-2.43), whereas the rapidly declining association was less precise (HR 1.24, 95% CI 0.80-1.92). Adding trajectory class to the MIMIC-IV clinical model increased the C-index from 0.786 to 0.792. After adjustment for first-day Hb, the rapidly declining trajectory remained associated with mortality (HR 1.77, 95% CI 1.20-2.62), whereas the persistently low association attenuated (HR 1.27, 95% CI 0.83-1.93). Independent three-class refitting in eICU did not recover the same latent-class structure (ARI 0.169).Conclusion Early Hb trajectories after TBI showed distinct prognostic associations. Persistently low Hb had the most consistent transported association but was attenuated after first-day Hb adjustment; rapid decline retained an association in MIMIC-IV but had limited external support. Incremental discrimination was modest. These patterns should be interpreted as treatment-embedded clinical courses rather than fixed biological phenotypes or evidence for trajectory-specific transfusion thresholds.
SN - 1664-2295
ER -