The relationship between hemoglobin-red blood cell distribution width ratio and short-term prognosis in patients with in-hospital cardiac arrest: a retrospective study

Abstract

Background:Cardiac arrest is a critical clinical condition with a grave prognosis, imposing a substantial burden on healthcare resources and society. Its underlying pathophysiology is characterized by the abrupt cessation of cardiac pump function, leading to systemic ischemia and hypoxia, particularly in the brain. This ischemic insult, in turn, activates a potent systemic inflammatory response that exacerbates organ injury. Conventional clinical parameters often fall short in providing a multidimensional assessment that concurrently addresses both inflammatory and ischemic-hypoxic risks, thereby limiting the identification of high-risk patients. The hemoglobin-to-red cell distribution width ratio (HRR) has recently emerged as a novel and integrated biomarker capable of reflecting systemic inflammatory activity and ischemic-hypoxic status. Although its prognostic value has been validated in various diseases, evidence regarding its association with outcomes following in-hospital cardiac arrest resuscitation remains scarce. Furthermore, existing studies predominantly focus on 30-day outcomes, leaving its role in predicting short-term prognosis underexplored. Therefore, this study aimed to investigate the impact of HRR on the short-term (7-day) prognosis of patients after cardiac arrest.

Methods:This study retrospectively analyzed data from adult in-hospital cardiac arrest patients who underwent successful cardiopulmonary resuscitation and achieved the return of spontaneous circulation at Yantai Yuhuangding Hospital between 2023 and 2025. The first available laboratory data after return of spontaneous circulation were collected. Significant variables affecting 7-day mortality were identified using univariate and multivariable Cox regression analyses. Additionally, Kaplan–Meier curves were used to further explore the impact of the HRR on the short-term mortality of the patients. Finally, a nomogram model incorporating HRR was developed for clinical prediction of in-hospital mortality risk.

Results:A total of 216 patients who met the inclusion and exclusion criteria were enrolled in this study. The multivariate Cox regression analysis revealed that HRR (hazard ratio: 0.887; 95% confidence interval: 0.845–0.931) and other factors were associated with the short-term mortality of the patients. After adjusting for relevant factors, it was found that Kaplan–Meier curves demonstrated that a decrease in HRR was correlated with an increased short-term mortality rate in the patients (P < 0.05).

Conclusion:The initial postresuscitation HRR (<9.13) level was significantly associated with an increased risk of short-term mortality in cardiac arrest patients.

Keywords

Cardiac arrest / Hemoglobin-to-RDW ratio / Mortality / Nomogram / Prognosis

Conflict of interest statement

The authors declare no conflict of interest.

Author contributions

Liu Q contributed to methodology, software, validation, formal analysis, data curation, visualization, and writing the original draft. Hu Y contributed to validation and visualization. Li Q contributed to conceptualization, investigation, resources, writing, review, and editing. Kang H contributed to supervision, writing, review, and editing. All authors have read and agreed to the published version of the manuscript.

Funding

None.

Ethical approval of studies and informed consent

The study followed the principles of the Declaration of Helsinki as revised in 2013. This study was approved and written informed consent was waived by the Ethics Committee of Yantai Yuhuangding Hospital Affiliated to Qingdao University (registration number: K2026-063, date: 2026-02-05) owing to the anonymized retrospective nature of the analysis.

Acknowledgments

None.

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