Joint effects of prognostic nutritional index and skeletal muscle index on prognosis of decompensated cirrhosis: a retrospective cohort study.

Background: Liver cirrhosis, characterized by chronic inflammation, is frequently complicated by malnutrition. Nutritional indices, such as the prognostic nutritional index (PNI) and the skeletal muscle index (SMI), calculated as the muscle area quantified via CT scans at the third lumbar vertebra level divided by the square of the patient's height in meters (cm²/m²), are associated with outcomes in inflammatory diseases.

Objectives: We aimed to evaluate the diagnostic efficacy of the PNI both independently and in combination with the SMI for identifying malnutrition in cirrhosis and to explore their prognostic implications.

Design: A single-center retrospective cohort study of 262 hospitalized cirrhotic patients (2018-2023). Malnutrition was assessed using PNI, PNI-SMI, and Global Leadership Initiative on Malnutrition (GLIM) criteria, respectively.

Methods: Nutritional status was defined by PNI (<28.85), PNI-SMI (either reduced PNI or SMI), and GLIM criteria. SMI was quantified via third lumbar vertebra CT scans. Diagnostic performance was evaluated using sensitivity, specificity, and area under the curve (AUC). Cox regression and Kaplan-Meier analyses assessed associations with 1-year mortality.

Results: The prevalence of malnutrition, as determined by various criteria, was considerably heterogeneous: 26.72% by the PNI, 56.11% by the PNI-SMI, and 51.14% by the GLIM criteria. Patients classified as malnourished demonstrated inferior clinical parameters and a higher 1-year mortality rate. The PNI-SMI combination exhibited favorable diagnostic performance in detecting malnutrition, with a sensitivity of 75.51%, specificity of 80%, along with an area under the curve of 0.774. Multivariate Cox analysis indicated that all three malnutrition criteria were independently associated with 1-year all-cause mortality, with hazard ratios of 2.56, 4.20, and 7.20, respectively.

Conclusion: The PNI, particularly when integrated with the SMI, offers a streamlined yet moderately accurate tool for nutritional and prognostic assessment in decompensated cirrhosis. This combined approach may serve as a practical supplement to GLIM criteria in select clinical contexts, potentially improving outcomes through targeted nutritional interventions.