Association between the lactate-to-albumin ratio and mortality in patients with protein-energy malnutrition: a retrospective cohort study

To evaluate the association between lactate-to-albumin ratio (LAR) levels and clinical outcomes in patients with protein-energy malnutrition (PEM). A retrospective analysis was conducted using the MIMIC-IV database. Patients with PEM were identified and stratified into four groups based on LAR quartiles. Cox regression models and restricted cubic spline (RCS) curves were employed to investigate the association between LAR and both 28-day ICU mortality and ICU mortality. Subgroup analyses were performed to compare the prognostic value of LAR across different populations. A total of 2,750 patients were included. Patients in the highest LAR quartile exhibited significantly higher 28-day ICU mortality and ICU mortality compared to those in the lowest quartile (both P < 0.001). After comprehensive adjustment for covariates, LAR remained significantly associated with 28-day ICU mortality (HR: 1.11, 95% CI: 1.01–1.22) and ICU mortality (HR: 1.19, 95% CI: 1.04–1.36) (both P < 0.05). Restricted cubic spline (RCS) curves indicated a non-linear relationship between LAR and both mortality outcomes. Sensitivity analyses further supported the robustness of the results. LAR was independently associated with increased 28-day ICU and ICU mortality in patients with PEM, exhibiting a non-linear relationship. These findings highlight the potential of LAR as an indicator for risk stratification in the PEM population.