Association of CONUT Score with Ultrasound-Measured Muscle Mass and 30-, 45-, and 60-Day Mortality in Geriatric Palliative Care Patients: A Prospective Observational Study

<b>Background/Objectives</b>: Early risk assessment of nutritional and muscular status in geriatric palliative care patients may facilitate timely, personalized care. This study aimed to evaluate the association between the CONUT score, ultrasound-assessed muscle mass, and short-term mortality at 30, 45, and 60 days. <b>Methods</b>: This prospective, single-center study was conducted in a tertiary palliative care unit between May and September 2024. Muscle mass was assessed via ultrasound by measuring the thickness and cross-sectional area of the rectus femoris and biceps brachii. Nutritional status was evaluated using the CONUT score (low: ≤4, high: ≥5). Mortality at 30, 45, and 60 days was analyzed using Kaplan-Meier curves, Cox regression, and ROC analysis. <b>Results</b>: In a cohort of 200 geriatric palliative care patients (mean age 78.4 ± 10.2 years; 54.5% female), those with higher CONUT scores (≥5) had significantly lower ultrasound-assessed muscle mass and higher short-term mortality rates (48.6% vs. 11.3%, <i>p</i> < 0.001). A CONUT score ≥ 5 and the presence of malignancy independently predicted mortality, with hazard ratios up to 3.72. The CONUT score demonstrated moderate predictive accuracy for short-term mortality, highest at 60 days (AUC = 0.736). Kaplan-Meier analysis revealed significantly reduced survival among patients with higher CONUT scores. <b>Conclusions</b>: A CONUT score ≥ 5 and malignancy independently predicted short-term mortality, and higher CONUT scores were associated with lower muscle mass. The CONUT score may be a useful tool for early risk assessment in geriatric palliative care, though further research is warranted.