Muscle Mass and Muscle Strength in Non-Dialysis-Dependent Chronic Kidney Disease Patients

Background: Sarcopenia is a state with a progressive and generalized loss of skeletal muscle mass and strength. However, muscle strength and muscle mass are different features, which are usually not studied separately. The aim of the study was to investigate anthropometric and clinical correlates and sources of variation in both skeletal muscle mass and muscle strength in chronic kidney disease (CKD). Methods: The study sample consisted of 84 patients with an estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m². Muscle strength was estimated by measuring hand grip strength (HGS). Muscle quantity was measured with bioimpedance spectroscopy (BIS). Serum creatinine, urea, uric acid (UA), and albumin were measured as well. Results: Appendicular skeletal muscle mass (ASM) significantly and positively correlated with body mass, NH weight (normally hydrated weight), height, body mass index (BMI), lean tissue mass (LTM), lean tissue index (LTI), fat mass (FM), and fat tissue index (FTI), and was negatively associated with hydration status. HGS significantly and positively correlated with body mass, NH weight, height, LTM, LTI, and ASM, and was negatively associated with UA and urea. After adjustment for age, sex, and height, HGS remained significantly and negatively related with UA and hydration status. Conclusions: In CKD patients, ASM is determined by anthropometric parameters, but HGS is determined by both anthropometric and clinical variables specific for CKD. In order to study the determinants of HGS in CKD, relationships with HGS should be adjusted for anthropometric variables.