Background: Our aim was to associate serum uric acid (UA) with muscle mass, strength and functional capacity in kidney transplant patients (KTPs). Methods: A cross-sectional study was performed on 113 KTPs. The fat-free mass and total and appendicular muscle mass were estimated by performing a bioelectrical impedance analysis. The strength was evaluated using the handgrip strength test (HGS) and the five times sit to stand test (5STS). The functional capacity was evaluated using the 4 m walk test and the short physical performance battery (SPPB). Results: Linear regression showed that the UA levels were positively associated with the muscle mass, fat-free mass, appendicular muscle mass, muscle mass index and appendicular muscle mass index. The 5STS results (seconds) were inversely associated with the UA levels, showing that individuals with higher UA were more likely to have more strength. However, UA was not associated with the HGS, 4 m walk test and SPPB results. Conclusion: UA levels were positively associated with muscle mass and strength, but not with functional capacity, in KTPs.

The biological meaning of phase angle (PhA) is not well known, and one determinant of PhA might be muscle function. However, the research is still in its infancy. The aim of this study was to evaluate the association of PhA with handgrip strength (HGS) in hospitalized individuals. We conducted a cross-sectional study evaluating 139 patients older than 18 years who were admitted to a university hospital. Weight, height, circumferences, and skinfolds were measured. In addition, PhA was estimated by bioelectrical impedance and HGS was measured using a dynamometer. Individuals were classified for lower PhA (median values; <6.0° for women and <5.7° for men) and low HGS (<20 kg for women and <30 kg for men). We found that PhA was positively correlated with HGS (r = 0.54; P < .05), and after regression analysis, PhA was able to predict 29% of the variance in HGS. In addition, it was noted that individuals with lower PhA values presented with higher odds to have low HGS values (OR = 4.152; 95% CI, 1.854-9.295). Thus, PhA was positively associated with HGS, suggesting that PhA might be used as a predictor of muscle strength in hospitalized patients.