Low testosterone at time of transplantation is independently associated with poor patient and graft survival in male renal transplant recipients.

Abstract

Low testosterone is common in men with renal disease and it increases the risk of death in those on dialysis. We studied serum testosterone at transplantation and correlated it with patient and graft outcomes. We identified serum samples collected and frozen at the time of transplantation in male recipients of primary kidney transplants done more than 6 years ago at our institution. In 197 recipients there was sufficient serum to determine total testosterone. We analyzed contingency outcomes by the Fisher exact test, continuous values by the Student t-test and survival by the Gehan-Breslow-Wilcoxon test. Mean patient age was 48.9 years (range 14 to 75). There were 100 living and 97 cadaveric donors, and 53 recipients (27%) had diabetes. Mean ± SD serum testosterone was 477 ± 251.3 ng/dl (range 48 to 2,013). Testosterone was low (less than 220 ng/dl) in 24 patients. Age did not correlate with testosterone. Low testosterone recipients had worse 1-year patient survival (75% vs 95%, p = 0.003), 3-year patient survival (62.5% vs 86.1%, p = 0.008), 1-year graft survival (62.5% vs 92.4%) and 3-year graft survival (50% vs 76.3%, p = 0.01). Survival curves showed significantly worse patient survival (p = 0.004) and graft survival (p = 0.02) for low testosterone. On multivariable analysis low testosterone was independently associated with patient death (HR 2.27, 95% CI 1.19-4.32) and graft loss (HR 2.05, 95% CI 1.16-3.62). Low testosterone at transplantation is associated with patient death and graft loss. If due to causality, testosterone therapy may impact survival. Without causality low testosterone may still be a marker for posttransplant risk.