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. 2025 Oct 24.
doi: 10.1007/s12028-025-02395-x. Online ahead of print.

Hematocrit-to-Hemoglobin Ratio as a Novel Independent Predictor for In-Hospital Mortality and Delayed Cerebral Ischemia in Critically Ill Patients with Aneurysmal Subarachnoid Hemorrhage Requiring Neurosurgical or Endovascular Treatment: A Retrospective Analysis

Emanuel Moisa  1   2 , Georgeana Tuculeanu  3   4 , Liliana Mirea  3   5 , Claudia Mihail  4 , Stefanita Dima  6 , Liviu Ioan Serban  4 , Dan Corneci  3   7 , Federico Bilotta  8 , Silvius Ioan Negoita  3   4
Affiliations

Hematocrit-to-Hemoglobin Ratio as a Novel Independent Predictor for In-Hospital Mortality and Delayed Cerebral Ischemia in Critically Ill Patients with Aneurysmal Subarachnoid Hemorrhage Requiring Neurosurgical or Endovascular Treatment: A Retrospective Analysis

Emanuel Moisa et al. Neurocrit Care. .

Abstract

Background: Substantial research has been dedicated to new prognostication tools in aneurysmal subarachnoid hemorrhage (aSAH), with a recent focus on laboratory parameters. Our study investigates the predictive value of a new hematological index, the hematocrit-to-hemoglobin (Ht-to-Hb) ratio, for mortality and delayed cerebral ischemia (DCI).

Methods: This is a retrospective, single-center, observational study on 78 adult critically ill patients with aSAH. We collected data from the electronic and written records, including demographic and clinical data, therapeutic measures, and intensive care unit and hospital length of stay. The primary outcome was in-hospital mortality, whereas the secondary outcome was DCI development. After descriptive analysis was performed, the Ht-to-Hb ratio was tested as a predictor for the primary and secondary outcomes. Firstly, we conducted a receiver operating characteristic analysis, and cutoff values were identified using the Youden index. Further, in-hospital mortality and DCI probability were evaluated using the log rank test. Cox proportional hazards regression was conducted to test the independent predictive value of the Ht-to-Hb ratio for the aforementioned outcomes.

Results: Mortality during hospitalization was 25.54%, whereas DCI frequency was 42.3%. The Ht-to-Hb ratio had areas under the receiver operating characteristic curve for death prediction and DCI of 0.85 and 0.734, respectively. Values greater than the cutoff value for mortality, 3.069, were independently associated with the primary outcome in the multivariable analysis (hazard ratio [HR] 4.64, 95% confidence interval [CI] 1.08-19.98, p = 0.039). For DCI, the cutoff value identified was 3.007. Ht-to-Hb ratios > 3.007 were an independent risk factor for DCI in the multivariable analysis (HR 3.86, 95% CI 1.43-10.4, p = 0.008).

Conclusions: The present study proposes a new prognostic index for mortality and DCI in aSAH: the Ht-to-Hb ratio. This marker could act as a surrogate for blood viscosity, uncovering the importance of blood rheology in aSAH pathogenesis.

Keywords: Aneurysmal subarachnoid hemorrhage; Blood viscosity; Delayed cerebral ischemia; Hematocrit-to-hemoglobin ratio; ICU; Rheology.

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Conflict of interest statement

Declarations. Conflicts of interest: The authors report no relevant conflicts of interest. Ethical Approval/Informed Consent: The study protocol was approved by the Local Ethics Committee of Elias Emergency University Hospital of Bucharest (study number 10108-2/01.08.2023) and in accordance with the ethical guidelines of the World Medical Association Declaration of Helsinki (1964). The requirement for informed consent from individual study participants was waived due to the retrospective and noninterventional nature of the study.

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