title: Low serum testosterone is associated with increased mortality in men with stage 3 or greater nephropathy.
abstract: BACKGROUND
  Chronic kidney disease (CKD) and low serum total testosterone (TT) concentrations are independent predictors of mortality risk in the general population, but their combined potential for improved mortality risk stratification is unknown.
  
  
  METHODS
  We used data of 1,822 men from the population-based Study of Health in Pomerania followed- up for 9.9 years (median). The direct effects of kidney dysfunction (estimated glomerular filtration rate <60 ml/min/ 1.73 m(2)), albuminuria (urinary albumin-creatinine ratio ≥2.5 mg/mmol) and their combination (CKD) on all-cause and cardiovascular mortality were analyzed using multivariable Cox regression models. Serum TT concentrations below the age-specific 10th percentile (by decades) were considered low and were used for further risk stratification.
  
  
  RESULTS
  Kidney dysfunction (hazard ratio, HR, 1.40; 95% confidence interval, CI, 1.02-1.92), albuminuria (HR, 1.38; 95% CI, 1.06-1.79), and CKD (HR, 1.42; 95% CI, 1.09-1.84) were associated with increased all-cause mortality risk, while only kidney dysfunction (HR, 2.01; 95% CI, 1.21-3.34) was associated with increased cardiovascular mortality risk after multivariable adjustment. Men with kidney dysfunction and low TT concentrations were identified as high-risk individuals showing a more than 2-fold increased all-cause mortality risk (HR, 2.52; 95% CI, 1.08-5.85). Added to multivariable models, nonsignificant interaction terms suggest that kidney dysfunction and low TT are primarily additive rather than synergistic mortality risk factors.
  
  
  CONCLUSIONS
  In the case of early loss of kidney function, measured TT concentrations might help to detect high-risk individuals for potential therapeutic interventions and to improve mortality risk assessment and outcome.
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, University of Greifswald, Germany. robin.haring@uni-greifswald.de
authors.forename: Robin
authors.initials: R
authors.lastname: Haring
authors.forename: Matthias
authors.initials: M
authors.lastname: Nauck
authors.forename: Henry
authors.initials: H
authors.lastname: Völzke
authors.forename: Karlhans
authors.initials: K
authors.lastname: Endlich
authors.forename: Uwe
authors.initials: U
authors.lastname: Lendeckel
authors.forename: Nele
authors.initials: N
authors.lastname: Friedrich
authors.forename: Marcus
authors.initials: M
authors.lastname: Dörr
authors.forename: Rainer
authors.initials: R
authors.lastname: Rettig
authors.forename: Heyo K
authors.initials: HK
authors.lastname: Kroemer
authors.forename: Henri
authors.initials: H
authors.lastname: Wallaschofski
mesh_terms: D015331:Cohort Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000401:mortality*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone