Limited Utility of the CALLY Index in Enhancing Mortality Prediction for Trauma Patients in Intensive Care Units: A Retrospective Analysis

Pao-Jen Kuo,* Ching-Ya Huang,* Kuan-Hao Liao, Pi‐Chieh Lin, Peng-Chen Chien, Ching-Hua Hsieh Department of Plastic Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan*These authors contributed equally to this workCorrespondence: Ching-Hua Hsieh, Email [email protected]: Accurate prognostication for trauma patients in intensive care units (ICUs) remains challenging. This study investigated whether incorporating the C-reactive protein-albumin-lymphocyte (CALLY) index into traditional ICU scoring systems could enhance mortality prediction for trauma patients.Methods: A retrospective cohort study was performed on 1242 trauma patients hospitalized to a Level I trauma center ICU from January 1, 2016, to December 31, 2023. The CALLY index was computed using the formula = [albumin (g/dL) × lymphocyte count (109/L)]/CRP (mg/L) and was incorporated with APACHE II, MPM II, MPM24 II, MPM48 II, and TRISS for predicting mortality outcomes. The predictive performance was assessed utilizing the area under the receiver operating characteristic curve (AUC).Results: Integration of the CALLY index with APACHE II resulted in a minimal AUC increase from 0.811 to 0.812. It did not alter the AUC for MPM II, MPM24 II, or MPM48 II models (0.826, 0.845, and 0.832, respectively). For TRISS, adding the CALLY index slightly decreased the AUC from 0.731 to 0.725. The calibration curves suggest that adding the CALLY index did not markedly improve agreement between predicted and actual mortality.Discussion: Unlike its proven efficacy in chronic conditions, the CALLY index did not significantly enhance mortality prediction in trauma patients when combined with traditional scoring systems. The reason that CALLY index did not enhance predictive power may be attributed to the acute, dynamic nature of trauma physiology, which differs from the steady-state conditions observed in chronic diseases. Further research is required to develop or refine prognostic tools specifically tailored to the unique physiological responses of trauma patients in ICU settings.Conclusion: For ICU clinicians, these results imply that the CALLY index provides minimal improvement in mortality risk assessment for trauma patients.Keywords: the C-reactive protein-albumin-lymphocyte index, CALLY index, trauma, intensive care unit, ICU, prognostic scoring systems, mortality