Objective:

To examine the association between red blood cell distribution width-to-albumin ratio (RAR) levels and in-hospital mortality risk in post-cardiac arrest patients.

Approach:

• Study Design: Retrospective cohort study using data from the eICU Collaborative Research Database, enrolling 2,508 cardiac arrest patients.
• Data Analysis: Patients categorized into tertiles based on RAR levels; logistic regression models and restricted cubic splines used to evaluate the association with mortality.

Key Findings:

• A nonlinear relationship between RAR and in-hospital mortality was identified.
• The association was stronger below the RAR threshold of 5.354.
• Each one-unit increase in RAR was associated with higher in-hospital mortality risk (adjusted OR = 1.16, 95% CI: 1.10–1.22).
• Patients in the highest RAR tertile had significantly higher mortality risk compared to those in the lowest tertile (P for trend <0.001).
• A marginally significant interaction between RAR and hypertension was observed (P for interaction = 0.038).

Interpretation:

Limitations:

• The study's retrospective design limits causal inferences.
• Modest predictive performance of RAR and negligible incremental value over albumin.
• Need for prospective external validation.

Conclusion: