Nonlinear association of the C-reactive protein-triglyceride-glucose index with 28-day mortality in critically ill children: a retrospective cohort study.

Background

The C-reactive protein-triglyceride-glucose index (CTI) has shown prognostic value in adults, but its association with short-term mortality in critically ill children remains unclear. We investigated the association of CTI with 28-day mortality, including its nonlinear relationship and incremental predictive value.

Methods

This retrospective cohort study included 5,039 critically ill children from the Pediatric Intensive Care database. Associations between CTI and 28-day mortality were evaluated via multivariable Cox regression, restricted cubic splines (RCS), and segmented two-piecewise Cox models. Competing-risk analysis, subgroup analyses, and sensitivity analyses were performed to test the robustness of results. Time-dependent AUC was used to evaluate model discrimination, while continuous NRI and IDI were calculated to determine the incremental predictive value. Calibration and decision-curve analysis were used to assess model performance and clinical utility.

Results

During the 28-day period after ICU admission, 227 patients (4.5%) died in hospital and 220 (4.4%) died in the ICU. In the fully adjusted model, compared with the lowest CTI tertile, the highest tertile was associated with higher risks of in-hospital mortality (HR 1.65, 95% CI 1.19-2.29; P = 0.003) and ICU mortality (HR 1.57, 95% CI 1.13-2.20; P = 0.008). Significant nonlinear associations were observed for both outcomes, with an exploratory breakpoint estimated at approximately 9.58. Adding CTI to the clinical model yielded only modest incremental predictive improvement.

Conclusions

Higher CTI was independently associated with 28-day mortality in critically ill children, with nonlinear associations and an exploratory breakpoint near 9.58, however the predictive value remained limited.