Mortality Prediction by Bedside Rectus Femoris Muscle Ultrasound for Sarcopenia Diagnosis in Liver Cirrhosis.

Background: Sarcopenia is common in patients with liver cirrhosis and is an independent predictor of morbidity and mortality. This prospective study assessed the performance of rectus femoris muscle (RFM) ultrasound in patients with liver cirrhosis to identify those at risk for sarcopenia as defined by the combination of low muscle mass and low muscle strength.

Methods: 84 patients with liver cirrhosis hospitalized at a tertiary center (05/22-02/24) were included with 6-month follow-up. Within 24-48 h of admission hand grip strength, chair rise test (CRT), timed up and go (TUG), short physical performance battery (SPPB), rectus femoris muscle ultrasound, and bioelectrical impedance analysis (BIA) were assessed. Statistical analyses included receiver operating characteristic (ROC) curves, Kaplan-Meier estimates, Cox regression, and competing risk analyses.

Results: Most (73.8%) patients had decompensated and mainly alcohol-related liver cirrhosis. Thickness and cross-sectional area of rectus femoris muscle (MT_RFM/CSA_RFM) were significantly (p < 0.01 each) lower in more advanced disease by Child-Pugh (CP) stage, also when normalized for height². MT_RFM/height² and CSA_RFM/height² demonstrated good predictive value for BIA-derived low muscle mass (ASMI < 7/5.7 kg/m²) or low phase angle ≤ 4.9° (AUROC 0.727-0.770). Impaired physical performance, in terms of prolonged CRT and TUG test time was associated with reduced MT_RFM or CSA_RFM (p < 0.05 each), respectively. Higher muscle echogenicity correlated with poorer performance in TUG and SPPB. Low rectus femoris muscle mass was associated with shorter survival and sarcopenic (prolonged CRT and low MT_RFM/height²) patients had a high 6-month mortality risk (HR 7.188; 95% CI 2.249-22.978).

Conclusion: Rectus femoris muscle ultrasound is a feasible bedside method for identifying patients with liver cirrhosis at risk of sarcopenia. Sarcopenia as diagnosed by prolonged CRT together with low RFM mass by ultrasound is an independent predictor for 6-month mortality, highlighting the clinical utility of RFM ultrasound in diagnosing sarcopenia.