Testosterone Replacement Therapy and Renal Function

Introduction to TRT and Renal Function

The American College of Physicians recommends considering the potential benefits of testosterone replacement therapy (TRT) in patients with chronic kidney disease (CKD), as low testosterone is associated with increased mortality and cardiovascular events, although the strength of evidence is moderate 1
TRT can cause fluid retention, which should be considered in patients with compromised renal or cardiac function, according to the American Heart Association, and use TRT cautiously in men with congestive heart failure or renal insufficiency, as recommended by the European Society of Cardiology 1

Monitor renal function at 3-6 month intervals during testosterone therapy, interpreting creatinine values in the context of increased muscle mass to avoid misinterpreting renal function, and consider using both creatinine and cystatin C-based GFR estimates for more accurate baseline assessment, as suggested by the National Kidney Foundation and the Kidney Disease: Improving Global Outcomes (KDIGO) guideline 1
Watch for unexplained decreases in eGFR not attributable to muscle mass changes, and consider discontinuing therapy if necessary, as recommended by various medical societies, including the European Society of Cardiology 2, 3

In patients with persistent severe secondary hyperparathyroidism, consider the potential risks and benefits of TRT, as recommended by the National Institute of Diabetes and Digestive and Kidney Diseases 3
Adjust TRT doses cautiously in cases of significant fluid retention in patients with compromised renal function, as suggested by the American Society of Nephrology, and avoid unnecessary adjustments to doses of renally-cleared medications based solely on creatinine-based eGFR, as advised by the European Renal Association and the American Cancer Society guidelines 1, 4
Testosterone therapy can lead to approximately 4 kg increase in lean body mass after 1 year, resulting in higher creatinine production and potentially affecting renal function, and cystatin C-based GFR estimation is recommended as it's less dependent on muscle mass, providing a more accurate assessment of renal function, according to the American Cancer Society guidelines 4
Establish baseline renal function before starting testosterone replacement therapy (TRT) to ensure proper monitoring and adjustment of treatment, as recommended by various medical societies, including the American College of Cardiology 4
Evaluate for other potential causes of renal dysfunction in patients with significantly elevated creatinine, and consider the effects of testosterone on renal function, including potential improvements in GFR and reductions in inflammatory markers, as recommended by the European Heart Journal guidelines 2, 4