Applied nutritional investigation determinants of lower quadriceps skeletal muscle measured by ultrasound at ICU admission: a cross-sectional analysis

Abstract

Background Low skeletal muscle (SM) is common at ICU admission and is associated with worse prognosis. Early identification of at-risk patients is essential, but determinants of low SM in critically ill patients remains unclear. Objective To identify sociodemographic, nutritional, and clinical characteristics associated with low SM at ICU admission. Methods This cross-sectional analysis included critically ill patients ≥18 years admitted within 24 hours. Sociodemographic and nutritional data were obtained through anamnesis, while clinical data were extracted from records. Quadriceps muscle layer thickness (QMLT) was measured using a B-mode US. Lower QMLT was defined as values below the sex-specific 25th percentile of the sample. Binary logistic regression was performed. Results 399 patients were included (age 61.4 ± 14.9 years; 56.6% male). Older age (OR = 1.02; CI 95% 1.0–1.04), previous unintentional weight loss (OR = 1.64; CI 95% 1.03–2.61), reduced food intake before admission (OR = 2.32; CI 95% 1.44–3.74), and pressure injuries (OR = 1.83; CI 95% 1.05–3.20) were associated with low QMLT. However, in multivariate analysis, only older age (OR = 1.02; CI 95% 1.00–1.04) and reduced food intake (OR = 2.26; CI 95% 1.22–4.18) remained independent determinants. Conclusion Older age and reduced food intake were independently associated with lower QMLT at ICU admission. These findings highlight the need for early screening and targeted strategies to mitigate muscle loss and improve outcomes in critically ill patients.