Phase angle, extracellular to intracellular water ratio, and advanced glycation end products according to four sarcopenia categories and in relation to muscle strength/mass in elderly out-patients with diabetes

Objective Sarcopenia is classified into normal, presarcopenia, dynapenia, and sarcopenia according to muscle strength/mass. As assessment methods for muscle strength and mass, phase angle (PhA), extracellular water/intracellular water ratio (ECW/ICW), and advanced glycation end products (AGEs) have been developed. We investigated the proportions in elderly outpatients with diabetes and elucidate clinical characteristics, including PhA, ECW/ICW, and AGEs among the four groups. Methods A cross-sectional study was performed in 695 patients with diabetes aged 65 years or older, who were classified according to the classification proposed by the Asian Working Group for Sarcopenia. Clinical characteristics of the four groups were compared by ANOVA. Associations of grip strength and skeletal muscle index (SMI) with PhA, ECW/ICW, and AGEs and interrelations among grip strength, SMI, PhA, ECW/ICW, and AGEs were analyzed by multiple linear regression analyses. Results Proportions of those (male/female, %) classified as normal, presarcopenia, dynapenia, and sarcopenia were 42.3/42.9, 30.3/26.6, 19.9/21.0, and 7.4/9.4, respectively. In order from normal, presarcopenia, dynapenia, and sarcopenia, age, ECW/ICW, and AGEs increased, while grip strength, gait speed, and PhA decreased ( p < 0.001). Grip strength had significant associations with PhA, ECW/ICW, and AGEs independent of the effect of age, sex, and SMI. SMI had significant associations with PhA and ECW/ICW, but not AGEs. ECW/ICW was independently associated with both grip strength and SMI, together with PhA and AGEs. Conclusions PhA, ECW/ICW, and AGEs were significantly different according to the four sarcopenia groups, and ECW/ICW was independently associated with both grip strength and SMI.