Objective:

To investigate the association of admission-based composite inflammatory indices and C-reactive protein-to-albumin ratio (CAR) with in-hospital mortality in adult patients admitted from the emergency department to the ICU.

Approach:

• Study Design: Retrospective cohort study including 709 adult patients admitted to the ICU via the emergency department.
• Indices Evaluated: Inflammatory and immuno-nutritional indices at admission, including CAR and three Multi-Inflammatory Index (MII) variants.
• Statistical Analysis: Unadjusted analyses, age- and sex-adjusted Cox regression models, and descriptive receiver operating characteristic analyses were used to assess associations with in-hospital mortality.

Key Findings:

• Non-survivors exhibited significantly higher median MII values and CAR levels compared with survivors (p < 0.001).
• In age- and sex-adjusted Cox regression analyses, CAR and all three MII variants were associated with in-hospital mortality.
• CAR showed the most consistent association with mortality, with an area under the curve (AUC) of 0.627, compared to MII variants with AUCs ranging from 0.579 to 0.595.

Interpretation:

MII variants and CAR were associated with mortality in admission-based analyses, but their discriminatory performance was limited.

Limitations:

• The study is retrospective and conducted at a single center, which may limit generalizability.
• Discriminative performance of the indices was modest.

Conclusion:

The findings indicate that admission-based inflammatory indices may serve as markers of inflammatory burden in emergency-to-ICU patients.