Association between lactate dehydrogenase to serum albumin ratio and all-cause mortality among critically ill pediatrics: a retrospective cohort study.

BACKGROUND: Although the lactate dehydrogenase-to-serum albumin ratio (LAR) has been associated with adverse outcomes in adult critical care, its prognostic value in pediatric intensive care unit (PICU) patients remains unclear. This study aimed to investigate whether admission LAR independently predicts 28-day all-cause mortality in critically ill children. METHODS: This retrospective cohort study analyzed 7,535 PICU admissions (2010–2018) from the Pediatric Intensive Care (PIC) database. LAR was calculated from laboratory values obtained within 24 h of admission. The primary outcome was 28-day in-hospital mortality. Multivariable Cox proportional hazards models, adjusted for potential confounders, were employed to calculate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). Kaplan-Meier survival analysis and subgroup analyses stratified by clinical covariates were performed to assess mortality risk stratification. RESULTS: The study cohort (median age 1.4 years [IQR 0.6–4.8]; 44.2% female) demonstrated an overall 28-day mortality rate of 4.5% (340/7,535). After full multivariable adjustment, each 1-log₂-unit increase in LAR was associated with a 32% higher mortality risk (adjusted HR 1.32; 95% CI 1.19–1.47; P < 0.001). Patients in the highest LAR tertile (≥ 12.62) exhibited 2.32-fold greater mortality risk compared with the lowest LAR tertile (< 8.02) (HR 2.32, 95% CI 1.71–3.16; P < 0.001). Kaplan-Meier curves revealed significantly poorer survival outcomes in high-LAR patients (log-rank P < 0.001). Subgroup analysis revealed no significant interactions (P for interaction > 0.05) except among pneumonia patients. Sensitivity analyses confirmed the robustness. CONCLUSIONS: Elevated admission LAR is an independent predictor of 28-day all-cause mortality in critically ill children, offering a readily available tool for early risk stratification.