title: Endogenous testosterone, muscle strength, and fat-free mass in men with chronic kidney disease.
abstract: OBJECTIVE
  Testosterone deficiency is a common finding in men with chronic kidney disease (CKD). Testosterone is thought to play an important anabolic role in muscle synthesis, and muscle wasting is an important and deleterious characteristic of protein-energy wasting (PEW) in CKD. It is presently unknown if reduced endogenous testosterone associates with features of muscle wasting in men with CKD.
  
  
  METHODS
  This was a cross-sectional observational study of 267 men with CKD stages 2-4 (mean ± standard deviation age 67 ± 13 years, estimated glomerular filtration rate 42.9 [interquartile range 30.2-56.7] mL/min/1.73 m²) with measurements of endogenous testosterone and surrogates of PEW such as albumin, prealbumin, high-sensitivity C-reactive protein (CRP) and normalized protein nitrogen appearance (nPNA). Fat-free mass was estimated by bioelectrical impedance vector analysis (BIVA) and muscle strength by handgrip dynamometry.
  
  
  RESULTS
  Across decreasing thirds of testosterone distribution, patients were incrementally older and CRP levels rose significantly. Prealbumin, hemoglobin, nPNA, handgrip strength, and BIVA estimated surrogates of muscle mass and nutritional status (fat-free mass, body cell mass, and phase angle) were progressively reduced (P < .05 for all). In multivariate regression analyses including age, renal function, and other important confounders, testosterone significantly and independently contributed to explain the variances of handgrip strength and fat-free mass (P < .05 for all).
  
  
  CONCLUSIONS
  Endogenous testosterone independently associates with muscle strength and fat-free mass in men with moderate CKD. It is plausible that the reduction in testosterone levels that accompanies CKD may further contribute to the procatabolic environment leading to muscle wasting.
authors.affiliation: Renal Medicine, Hospital Da Costa, Burela, Spain.
authors.forename: Secundino
authors.initials: S
authors.lastname: Cigarrán
authors.forename: Montserrat
authors.initials: M
authors.lastname: Pousa
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Castro
authors.forename: Berta
authors.initials: B
authors.lastname: González
authors.forename: Aurelia
authors.initials: A
authors.lastname: Martínez
authors.forename: Guillermina
authors.initials: G
authors.lastname: Barril
authors.forename: Abelardo
authors.initials: A
authors.lastname: Aguilera
authors.forename: Francisco
authors.initials: F
authors.lastname: Coronel
authors.forename: Peter
authors.initials: P
authors.lastname: Stenvinkel
authors.forename: Juan Jesús
authors.initials: JJ
authors.lastname: Carrero
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001835:Body Weight; D002097:C-Reactive Protein / Q000378:metabolism; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005919:Glomerular Filtration Rate; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009752:Nutritional Status; D010641:Phenotype; D011446:Prospective Studies; D012044:Regression Analysis; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology; D012307:Risk Factors; D013739:Testosterone / Q000097:blood* / Q000172:deficiency
chemical_list: D013739:Testosterone; D002097:C-Reactive Protein