Clinical Nutrition ESPEN · May 16, 2025

Low skeletal muscle and subcutaneous fat at admission are associated with 90-day mortality in intensive care unit patients

By Thibault R, Pereira B, Som M et al.

BACKGROUND: Low muscle mass assessed by the third lumbar vertebra (L3)-targeted abdominal computed tomography-scan (CT-scan) predicts short-term hospital mortality in the intensive care unit (ICU) patients. However, little is known regarding the relation between the L3 muscle and fat areas at ICU admission and 90-day clinical outcomes. AIMS: to determine the relation between skeletal muscle, subcutaneous, visceral, intramuscular, and total fat cross-sectional areas at ICU admission and 90-day mortality (main), between skeletal muscle and other clinical outcomes, and between body mass index (BMI) and 90-day mortality (secondary). METHODS: A retrospective observational study was performed in a 10-bed medical ICU. The inclusion criteria were: routine abdominal CT-scan <3 days post-admission, expected length of stay >48 h. CT-scan assessed skeletal muscle, subcutaneous, visceral and intramuscular fat areas (cm²) at the L3 level. Low skeletal muscle index (SMI) was defined as <38.5 (women) and <52.4 cm²/m² (men). Actuarial survival curves, univariate analyses and multivariable Cox models were performed. RESULTS: Out of 200 screened patients, 141 were analyzed: age (mean ± standard deviation) 65.2 ± 14.9 years, 59 % of males, Simplified Acute Physiology Score (SAPS) II 61.7 ± 21.5, BMI, 27.9 ± 6.4. Kaplan-Meier analysis indicated worse survival in patients with low skeletal SMI (61 % (n = 39/64) vs. 44 % (n = 34/77), P = 0.04). Cox multivariable analysis indicated that age ≥65 years (hazard ratio (HR) = 1.79 [95 % confidence interval, 1.01 - 3.19], P = 0.047), SAPS II (HR = 1.04 [1.02-1.05], P < 0.001), low SMI (normal vs. low, HR = 0.48 [0.29-0.82], P = 0.007) and subcutaneous fat index log (HR = 0.67 [0.51 - 0.89], P = 0.006), were independently associated with 90-day mortality. Visceral, intramuscular and total fat areas were not associated with 90-day mortality. Higher body mass index was associated with lower 90-day mortality (HR = 0.92 [0.88-0.96, P < 0.001], when the model excluded muscle and fat tissue levels. CONCLUSIONS: Lower skeletal muscle mass, subcutaneous fat and BMI at ICU admission are associated with higher 90-day mortality. Despite the Global Leadership Initiative on Malnutrition criteria were not used, these results suggest that protein-energy malnutrition at ICU admission is a strong marker of mortality.

doi.org/10.1016/j.clnesp.2025.05.015 Open access PubMed 40383258 Biomarkers