# Emergency risk stratification using the TyG index: a multi-center cohort study on nonlinear association with 28-day mortality among critically ill patients transferred from the ED to the ICU

## TL;DR

This study shows that the TyG index, a marker of insulin resistance, can help predict 28-day mortality in critically ill patients transferred from the emergency department to the ICU.

## Contribution

The study reveals a nonlinear relationship between the TyG index and mortality risk, identifying a critical threshold for risk stratification in ED-to-ICU patients.

## Key findings

- The TyG index has a nonlinear association with 28-day mortality, with increased risk up to a threshold of 9.84.
- Mortality risk plateaus above a TyG index of 9.84, indicating a saturation effect.
- The association remains robust after adjusting for confounders and across sensitivity analyses.

## Abstract

In the emergency department (ED), rapid risk stratification of critically ill patients is essential for timely intervention. The triglyceride-glucose (TyG) index, a simple marker of insulin resistance, may aid in early mortality prediction, but its utility in ED-to-ICU patients remains unexplored.

Using data from the eICU Collaborative Research Database, we conducted a retrospective multicenter cohort study of 11,593 ED-to-ICU critically ill patients. The TyG index was calculated at ED presentation. The primary outcome was 28-day all-cause mortality. Multivariable Cox regression, restricted cubic splines, and sensitivity analyses were performed to assess associations.

Among patients (mean age 63.6 ± 15.7 years, 57.3% male), 28-day mortality was 6.96%. The relationship between the TyG index and mortality was nonlinear, featuring a critical threshold at a TyG index value of 9.84. Below this cutoff, each unit increase in TyG index significantly elevated mortality risk (HR 1.47, 95% CI 1.20–1.69, p < 0.0001), while above it, the risk plateaued (HR 1.04, 95% CI 1.03–1.05, p = 0.097). The association remained robust after adjustment for confounders (adjusted HR 1.19, 95% CI 1.04–1.35, p = 0.0089) and across sensitivity analyses.

The TyG index, readily obtainable at ED presentation, provides emergency clinicians with a practical tool for early mortality risk stratification in critically ill patients. Its nonlinear association with 28-day mortality suggests a saturation effect, enabling rapid identification of high-risk patients who may benefit from intensified monitoring and intervention.