Association of Total Serum Testosterone with Muscle Mass and Strength in Renal Transplant Recipients

Stam, S.P. (Suzanne) (2017) Association of Total Serum Testosterone with Muscle Mass and Strength in Renal Transplant Recipients. thesis, Medicine.

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Abstract

Background. Muscle mass, as determined by 24h urinary creatinine excretion (UCE), is an independent predictor for mortality and graft failure in renal transplant recipients (RTR). Meanwhile, RTR may also still suffer from complications acquired during kidney disease, such as hypogonadism. The aim of this study is to investigate whether total serum testosterone is associated with muscle mass and muscle strength in stable RTR. Furthermore, we aim to investigate whether levels of testosterone after transplantation differ from those in healthy controls. Methods. RTR who were transplanted between 1975 and 2015 in the University Medical Center Groningen were included for cross-sectional analyses. UCE was determined by 24h urinary creatinine excretion. Total serum testosterone was measured by liquid chromatography combined with mass spectrometry. Muscle strength was assessed by handgrip strength and sit-to-stand test. Statistical analyses were performed using linear regression analyses, followed by multivariable backward regression. Results. We included 184 RTR (mean age 56.9 ± 11.9 years and 54% was male) and 96 healthy controls. Median time after transplantation was 4.0 (1.1-8.8) years. Mean UCE was 12.9 ± 4.0 mmol/24h for men and 9.5 ± 2.9 mmol/24h for women. Further baseline analyses were performed using sex-stratified tertiles. Crude analysis showed a strong association of serum testosterone and muscle mass (std. β 0.43; P<0.001), but this association was lost after adjustment for age and sex (std. β -0.02; P=0.92). The same held true for the association of serum testosterone with handgrip strength (std. β 0.55; P<0.001 before adjustment for age and sex and std. β -0.05; P=0.74 after adjustment). Serum testosterone was not associated with the time according to the sit-to-stand test (std. β -0.06; P=0.55). Androgen parameters were lower on all accounts compared to healthy controls, except for median levels of testosterone in male RTR (12.8 (10.1-16.7) versus 13.9 (12.3-16.3), resp.; P=0.33) respectively. High urinary urea excretion (UUE) reflecting high protein intake, low age, high body surface area (BSA), male sex, and absence of insulin use were identified as independent predictors of high muscle mass in RTR. Conclusions. Serum testosterone is neither independently associated with muscle mass nor with muscle strength in RTR. Additionally, androgen parameters may be on sufficient levels for male RTR, but are low in female RTR. UUE, age, BSA, sex, and insulin use are independent predictors of muscle mass in RTR. These novel results may be an encouragement to further investigate factors underlying maintenance of muscle mass and strength in RTR.

Item Type:	Thesis (Thesis)
Supervisor name:	Supervisors: and Bakker, Prof. dr. S.J.L. and Eisenga, M.F. MSc and Department: and Internal Medicine, division of Nephrology and Institution: and University Medical Center Groningen
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:50
Last Modified:	25 Jun 2020 10:50
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/1072

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