Evaluation of Dynapenia and Sarcopenia and Their Associations With Serum Insulin-Like Growth Factor-1 Levels in Renal Transplant Recipients.

OBJECTIVES: Dynapenia and sarcopenia are related to increased morbidity and mortality in the general population. Chronic kidney disease (CKD) causes sarcopenia and dynapenia with different mechanisms. The aim of this study is to compare the muscle parameters in renal transplant recipients to CKD patients and patients without kidney disease and assess their associations with serum insulin-like growth factor-1 (IGF-1) levels. METHOD: In total, 120 renal transplant recipients (mean age: 40.4 ± 10.5 years), 60 CKD patients (mean age: 41.9 ± 11.4 years), and 60 control subjects with normal kidney function (mean age: 38.8 ± 9.9 years) were enrolled. Body mass index, hand grip strength, bioelectrical impedance analysis, 6-minute walking test, and serum IGF-1 level were measured and compared between groups. Muscle parameters were evaluated according to The Foundation for the National Institutes of Health Biomarkers Consortium Sarcopenia Project criteria. RESULTS: IGF-1 levels were highest in the renal transplantation group and lowest in the control group (P = .029). In total, 12.5% of patients in the renal transplantation group (13.3% overweight, 20% obese), 11.6% in the CKD group, and 1.6% in the control group had dynapenia (P = .015). In addition, 8.3% of patients in the CKD group, 3.3% in the renal transplantation group (50% overweight), and none of the patients in the control group had sarcopenia (P = .054). In multivariate analyses, muscle strength was associated with IGF-1 levels in renal transplant recipients (beta = 2.314, t = 3.456, P = .001). CONCLUSIONS: Serum IGF-1 is closely associated with muscle strength in renal transplant recipients. The negative effects of CKD on muscle system cannot be completely resolved with renal transplantation. Sarcopenic obesity and dynapenic obesity need special attention and therefore body mass index cannot be used as the only parameter to evaluate frailty in renal transplant recipients.