RESUMEN
BACKGROUND: The muscle quality index (MQI) has proven to be an interesting clinical measurement in hemodialysis (HD) patients. In clinical practice, its interpretation can be biased by fat mass (FM) distribution. This study aims to explore the arm MQI association with body composition, clinical factors, and mortality. METHODS: It was analytical longitudinal and exploratory, that included patients from two-center, over 18 years old, of both genders in treatment by HD. The follow-up period was 32 months, and mortality was the clinical outcome. Demographical and clinical data were collected in the patient's medical records. Body composition was evaluated using octopolar multi-frequency bioelectrical impedance analysis (MF-BIA). Handgrip strength (HGS) was measured by a dynamometer and the time required to walk 3 m was applied to obtain gait speed. The baseline associations with MQI (HGS/arm muscle mass) were examined by multivariate linear regression. Cox regressions evaluated the associations with mortality. RESULTS: A total of 97 patients in HD were included. Mean age was 50.93 ± 14.10 years, 71.13 % were male. Age (ß = -0,096, p = 0.024), HD time (ß = -0.023, p = 0.032), total skeletal muscle mass (ß = -0.475, p < 0.001) were inversely associated with MQI and gait speed had a direct association with MQI (ß = 8514, p = 0.002). The prevalence of mortality was 29.76 %, of which 37.29 % were men (p = 0.020). Low MQI was not associated with mortality (Hz = 0.80, CI95 % = 0.34; 1.91, p = 0.629). CONCLUSION: The arm MQI was associated with an indicator of general functional capacity (gait speed), but was not associated with fat measures in baseline and mortality after 32 months of follow-up.