The impact of sirolimus on sex hormones in male adolescent kidney recipients

Abstract

While it is known that sirolimus affects sex hormones in adult kidney transplant patients, there is a scarcity of data on its effects on sex hormone levels in adolescent kidney recipients. The objective of this study is to describe the impact of sirolimus on the sex hormones in this patient population. This is a retrospective review of male adolescent renal transplant patients transitioned to sirolimus. Baseline and subsequent annual testosterone levels were collected. Linear regression was undertaken to determine the predictors of testosterone levels. Four African Americans and 11 Caucasians, median age of 15 yr (11-18) in 2008, were included. Mean time post-transplant was 81 ± 37 months. Mean testosterone values were the following: 336 ± 135 ng/dL (n = 8) at baseline, 349 ± 130 ng/dL (n = 15) one yr later, and 360 ± 132 ng/dL (n = 13) two yr later (normal range for adult males: 350-970 ng/dL). Seven (47%) patients experienced a decrease in testosterone levels. Time on sirolimus was associated with decreased testosterone (r = 0.643, p = 0.010). Testosterone levels in pubertal male kidney transplant recipients on sirolimus may be suppressed, especially if they have been treated with sirolimus for several years. These data need to be confirmed in a larger study.