Muscle Mass Deficit Indexed to Body Surface Area Predicts Poor Physical Health and Quality of Life in Hemodialysis Patients.

INTRODUCTION: Hemodialysis patients experience significantly lower quality of life compared to the healthy individuals, largely due to symptoms such as bone pain, fatigue, pruritus, anorexia, inflammation, malnutrition, and anemia. This study aimed to investigate the effects of sarcopenia and low muscle mass on quality of life, with a particular focus on physical health indices. METHODS: The study included 62 patients on maintenance hemodialysis. Sarcopenia was diagnosed using the fat-free mass index (FFMI), defined as skeletal muscle mass divided by height squared (kg/m²). Additionally, skeletal muscle mass was normalized to body surface area (BSA); values below the sample mean of 46.12 kg/m² were classified as low muscle mass. Quality of life was assessed with the Kidney Disease Quality of Life (KDQOL) Version 1.3 questionnaire and scored using the KDQOL-SF™ Version 1.3 Scoring Program. RESULTS: Sarcopenia was present in 18 patients (29%) according to FFMI. Patients scored lowest in general health (35.6), energy/fatigue (40.9), and both SF-12 physical (37.5) and mental health (37.2) domains. Sarcopenic patients reported significantly higher pain scores (60.97 ± 29.54 vs. 46.19 ± 27.37; P = .046), but other domains did not differ. Patients with low muscle mass/BSA (kg/m2) had lower sleep (51.5 ± 11.7 vs. 59.6 ± 13.0; P = .01), energy/fatigue (35.6 ± 20.1 vs. 52.8 ± 20.7; P = .005), and SF-12 physical health scores (35.7 ± 9.0 vs. 40.6 ± 8.3; P = .03). Muscle mass indexed to BSA was an independent predictor of the SF-12 physical health composite score. CONCLUSION: Low muscle mass, particularly when indexed to BSA, is associated with reduced physical health in hemodialysis patients and poorer quality of life across multiple domains. BSA-indexed muscle mass showed stronger and more consistent associations than FFMI-based definitions.