Factors associated with an improvement in extracellular water-to-total body water ratio in older adults with hip fractures: A decision tree analysis.

ABSTRACT

BACKGROUND & AIMS: The extracellular water-to-total body water ratio (ECW/TBW) increases with age and after fractures. A high ECW/TBW may hinder improvements in physical function and skeletal muscle mass. However, the effects of ECW/TBW improvement have not been properly investigated. The aim of this study was to investigate the factors associated with ECW/TBW improvement in older adults with hip fractures. METHODS: This retrospective cohort study included 203 patients with hip fractures who were admitted to a convalescent rehabilitation ward. ECW/TBW and skeletal muscle mass index (SMI) were measured using bioelectrical impedance analysis. The patients were classified into two groups those with an improvement in ECW/TBW (n = 123) and those without an improvement (n = 80). Decision tree analysis was performed to examine the factors associated with ECW/TBW improvement. As a secondary objective, a multiple regression analysis was performed to identify the factors associated with SMI gain. RESULTS: Decision tree analysis identified rehabilitation volume and protein intake as the first and second factors most significantly associated with an improvement in ECW/TBW, respectively. Multiple regression analysis showed that improved ECW/TBW (ß 0.400, p < 0.001) was significantly associated with SMI gain. CONCLUSIONS: Rehabilitation volume and protein intake are clinically important for improving ECW/TBW in older adults with hip fractures.