The association between serum testosterone and mortality among elderly men on hemodialysis

ObjectivesThis study examines the associations between total testosterone levels and dialysis mortality. MethodsElderly men who initiate hemodialysis in Taoyuan General Hospital from January 2012 to June 2017 were enrolled. We reviewed clinical characteristics and biochemical data from start of dialysis and followed over a 5-year period after dialysis. Body composition parameters were assessed 3-6months after dialysis. Skeletal muscle mass index (SMMI) was defined by skeletal muscle mass divided by squared height. We defined those with lowest tertile of testosterone values as low testosterone group. Adjusted hazard ratios (aHRs) and 95% confidence interval (95% CI) for mortality and cumulative survival curves were evaluated by Cox hazards model and Kaplan-Meier method. The discriminative power of SMMI and testosterone levels was calculated according to the area under the curve and the receiver operating characteristic curve (AUROC). ResultsFrom a total of 137 elderly hemodialysis patients, the range of lowest, middle, and highest tertile of testosterone values was <6.25nmol/L, 6.25-10.5nmol/L, and >10.5nmol/L. After multivariate adjustment other than SMMI, total testosterone levels at baseline were a significant predictor for mortality aHR(95% CI): 0.79 (0.70-0.91). The unadjusted and adjusted c-statistics of SMMI vs testosterone values to predict overall were 770 (0.688-0.852) vs 0.779 (0.691-0.866) and 855 (0.812-0.886) vs 0.812 (0.744-0.856) (Ps<.05), whereas the capacity of c-statistics was similar ((2)=0.143 and 2.709, Ps>.05). ConclusionsTotal testosterone value was a predictor for mortality. It was noninferior to SMMI in predicting dialysis mortality.