RESUMO
OBJECTIVE: Our objective was to characterize and evaluate prognostic implications of circulating sex steroids in patients at different stages of chronic kidney disease (CKD). DESIGN: Prospective observational cohort study. PATIENTS: We prospectively recruited patients with CKD III-IV, undergoing chronic dialysis and kidney transplant recipients (KTR) from a single centre in 2003-2004. MEASUREMENTS: Two stored samples taken 3 months apart were analysed for sex hormones using liquid chromatography/tandem mass spectrometry, and the mean of the two was used for analysis. We also measured novel biomarkers troponin T and NT-proBNP. Patients were followed until death, transplant or 30 June 2013, and survival analysis performed. RESULTS: In males, but not in females, both testosterone (P = 0·003) as well as oestradiol (P < 0·02) levels were lowest in dialysis patients and highest in KTR. Over a median follow up of 8·5 years (interquartile range 3·8-9·2), 52 men (36%) died and 24 (17%) received a kidney transplant. In Cox proportional hazards regression up to 9·6 years, an increase in total testosterone of 1 nmol/l was associated with a 9·8% (95% confidence interval 3·1-16·3) decrease in mortality independent of age, body mass index, stage of renal disease and circulating levels of NT-proBNP or troponin T. By contrast, sex steroid levels were not associated with mortality in females. CONCLUSIONS: Testosterone levels differ across stages of kidney disease and low testosterone levels predict mortality in males, independent of established and novel predictors of mortality.
