Combined Assessment of Skeletal Muscle Mass Index and Extracellular-to-Intracellular Water Ratio Predicts Mortality and Health-Related Quality of Life in Hemodialysis Patients

KEY POINTS: Both low skeletal muscle mass index and high extracellular and intracellular water independently predicted mortality; risk was highest when both abnormalities were present. Extracellular and intracellular water ≥0.66 indicated impaired muscle tissue integrity and helped identify vulnerable patients. Combining skeletal muscle mass index with extracellular and intracellular water identified patients with lower health-related quality of life across multiple domains. BACKGROUND: Decreased skeletal muscle mass is common in hemodialysis patients and contributes to adverse outcomes. However, muscle mass alone does not fully capture muscle health. An imbalance between extracellular and intracellular water (ECW/ICW ratio) may reflect tissue-level integrity of skeletal muscle. This study examined the combined prognostic significance of the skeletal muscle mass index (SMI) and ECW/ICW ratio for mortality and health-related quality of life (HRQoL) in hemodialysis patients. METHODS: In this multicenter cohort study, 295 maintenance hemodialysis patients (208 men, 87 women) underwent multifrequency bioelectrical impedance analysis. Low SMI was defined according to the Asian Working Group for Sarcopenia (men