BIA and definition of edema index

BIA was performed on the day of admission before intravenous hydration using a multi-frequency BIA InBody 770 scanner (InBody, Seoul, Republic of Korea). BIA was performed with patients in a standing position according to the manufacturer’s instructions after shoes, coats, and sweaters had been removed. The BIA scanner used frequencies 1, 5, 50, 260, 500, and 1,000 kHz over 60 seconds. By BIA, phase angle, extracellular fluid and total body fluid, body cell mass, and appendicular skeletal muscle mass can be derived by computed analysis. Edema index can be calculated as the ratio of extracellular fluid to total body fluid. Sarcopenia was defined using height-adjusted appendicular skeletal muscle mass (appendicular skeletal muscle mass/height², kg/m²), and was <7.0 kg/m² for men and <5.7 kg/m² for women according to a previous study involving Asians (26).