Treatment of hypogonadism in men with chronic kidney disease

Sex Differences in the Association Between Serum Testosterone and Kidney Function in the General Population

Introduction

Testosterone might prevent kidney function decline, although evidence is limited in men and lacking in women from the general population. We investigated the association between serum testosterone and kidney function in men and women from a large population-based cohort study.

Methods

Participants aged ≥45 years with available measurements of serum testosterone, sex hormone-binding globulin (SHBG), creatinine, and cystatine C were included. Assessments of kidney function included baseline assessments of the estimated glomerular filtration rate (eGFR) based on serum creatinine (eGFRcreat) or serum cystatin C (eGFRcys), and the urine albumin-to-creatinine ratio (ACR), and repeated assessments of eGFRcreat. Linear regression and linear mixed models were used to assess the associations of serum free and total testosterone with kidney function, stratified for sex.

Results

A total of 4095 men and 5389 women (mean age 65.2 years) were included. In men, higher free testosterone was associated with lower eGFRcreat (beta -0.63, 95% confidence interval [CI]: -1.05; -0.21), higher eGFRcys (beta 0.56, 95% CI: 0.07; 1.05), and lower ACR (beta -0.25, 95% CI: -0.35; -0.16) at baseline. Higher total testosterone was associated with higher baseline and follow-up eGFRcreat, and with lower eGFRcreat when additionally adjusted for SHBG. In women, higher free testosterone was associated with lower baseline eGFRcreat and eGFRcys (beta -1.03, 95% CI: -1.36; -0.71; beta -1.07, 95% CI: -1.44; -0.70; respectively) and lower eGFRcreat over time (beta -0.78, 95% CI: -1.10; -0.46), but not with ACR.

Conclusions

eGFRcys might be a better parameter than eGFRcreat for the association of testosterone with kidney function, although further studies investigating this are needed. Furthermore, we identified sex differences in the association between testosterone and kidney function, with a positive association in men and a negative association in women.

Testosterone Deficiency as One of the Major Endocrine Disorders in Chronic Kidney Disease

Reduced testosterone concentration is nowadays thought to be one of the main endocrine disorders in chronic kidney disease (CKD). It is caused by the dysfunction of the hypothalamic-pituitary-gonadal axis. The role of testosterone is multifactorial. Testosterone is responsible not only for reproductive processes, but it is a hormone which increases bone and muscle mass, improves lipid profile, insulin sensitivity, erythropoiesis, reduces blood pressure, and ameliorates mood and perception. The implications of hypogonadism in CKD are infertility and loss of libido, reduction of muscle mass and strength, disorders in bone mineralization, the development of sarcopenia and protein energy wasting (PEW), progression of atherosclerosis, increased visceral adiposity, insulin resistance, and anaemia. Reduced testosterone serum concentrations in CKD are associated with increased mortality rate. Testosterone supplementation improves sexual functions, reduces the level of inflammatory markers and blood pressure, stimulates muscle protein synthesis, improves insulin sensitivity and lipid profile, and increases muscle mass, bone mineral density, and haemoglobin concentration. It positively affects mood and well-being. The modes of testosterone supplementation are intramuscular injections, subcutaneous pellets, and percutaneous methods—patches and gels. Successful kidney transplantation may improve gonadal function and testosterone production, however, half of men with low testosterone concentrations before kidney transplantation do not restore hormonal function.

The role of serum testosterone and dehydroepiandrosterone sulfate in kidney function and clinical outcomes in chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE/DESIGN

Testosterone might mediate sex differences in kidney function and chronic kidney disease (CKD). However, few studies analyzing the association between testosterone and kidney function showed conflicting results. Therefore, we performed a systematic review and meta-analysis.

METHODS

Six electronic databases were searched from inception to March 4, 2020, for studies that investigated the association of (i) testosterone status with kidney function in the general population or (ii) testosterone status with clinical outcomes (kidney function decline, kidney failure, cardiovascular (CV) events, and cardiovascular and all-cause mortality) in CKD patients. We used random and fixed-effect models to obtain pooled effect estimates with 95% confidence intervals (CIs).

RESULTS

No randomized-controlled trials that met the inclusion criteria were identified. One study was conducted in the general population and reported an increased risk of incident CKD with low vs normal testosterone (hazard ratio (HR): 1.38, 95% CI: 1.05;1.80). Seven studies were conducted in men with CKD and included testosterone as determinant, of which six could be meta-analyzed. Low testosterone was associated with an increased risk of all-cause mortality and CV events (pooled HR: 1.98, 95% CI: 1.36;2.89; pooled HR of 2.40, 95% CI: 1.22;4.71, respectively). Two studies showed an increased risk of all-cause mortality with decreased dehydroepiandrosterone sulfate (DHEAS) in men with CKD; results regarding CV events were conflicting.

CONCLUSIONS

Although literature is scarce, evidence suggests that lower testosterone may increase CKD risk in the general population and risk of all-cause mortality and CV events in men with CKD. Whether testosterone supplementation could prevent these potential detrimental outcomes should be determined in future intervention studies.

Sexual Dysfunction Among Patients With Chronic Kidney Disease

Sexual dysfunction (SD) in patients with chronic kidney disease is common and negatively impacts quality of life. SD is often under-appreciated because of overall low awareness. Diagnosis of SD is subjective, and manifestations can be different among men and women. Causes of SD are multifactorial, including psychological disorders, hormonal imbalances, vascular disorders, neurological disorders, and medication side effects. Non-specific approaches to improving sexual function include addressing underlying psychological disorders, promoting lifestyle modifications, optimizing dialysis care, and facilitating successful kidney transplantation, whereas treatment with phosphodiesterase type 5 inhibitor, hormone replacement, and mechanical devices can be offered to patients with specific indications.

Changes in fertility and hormone replacement therapy in kidney disease

Infertility is common among men and women with CKD and fertility is usually restored with successful kidney transplantation. There are many causes of infertility in those on dialysis, including sexual dysfunction and impaired spermatogenesis and ovulation resulting from an altered hormonal milieu. There is little information about infertility in CKD, but it is clear that ESRD results in low rates of pregnancy in women. Early reports of increased pregnancy rates in women on nocturnal hemodialysis suggest that this modality may improve the abnormal reproductive hormonal milieu of ESRD; small studies of men on dialysis also suggest this. Just as the specific causes of infertility in men and women with CKD/ESRD are unknown, we also lack information about the appropriateness of hormone replacement in these patients. This paper reviews these linked issues, pointing out the lack of data upon which to base clinical decision-making about these quality-of-life issues in our CKD/ESRD patients.

Creatinine and nonprotein nitrogen plasma levels: possible etiopathogenetic factors in rotator cuff tears

OBJECTIVE

To determine the plasma levels of nonprotein nitrogen (NPN) and creatinine in healthy patients with rotator cuff tears.

METHODS

The study included 400 subjects. The study group included 200 patients (93 men and 107 women; mean age, 56.8 years; range, 23-81 years) who underwent arthroscopic repair of a rotator cuff tear from 2004 to 2007. The control group included 200 patients (93 men and 107 women; mean age, 53.9 years; range, 20-81 years) who underwent arthroscopy for management of a meniscal tear, with or without articular cartilage damage, in the same period. The 2 groups were frequency-matched by age and sex. Measurement of plasma levels of NPN and creatinine were performed in all patients.

RESULTS

Patients with rotator cuff tears showed higher plasma NPN levels within the normal range (P = 0.035) than patients with knee disorders (control group). Creatinine levels were comparable (P = 0.66) in both groups.

CONCLUSION

There appears to be an association between plasma NPN levels and rotator cuff tears. On the basis of our findings, plasma NPN could be involved in the pathogenesis of rotator cuff tears, although we advocate further research to draw more definitive conclusions.

Sexual function in chronic kidney disease

Endocrine abnormalities are common in patients with chronic kidney disease (CKD) and lead to sexual dysfunction, anemia, hyperparathyroidism, and altered mineral metabolism. Common clinical problems include disturbances in menstruation in women, erectile dysfunction in men, and decreased libido and infertility in both sexes. Organic factors tend to be prominent and are related to uremia and other comorbid illnesses. Psychological factors and depression may exacerbate the primary problem. Alterations in the hypothalamic-pituitary axis are seen early in CKD and tend to worsen after patients start dialysis. Hypogonadism plays a dominant role in male sexual function, whereas changes in hypothalamic-pituitary function predominate in female sexual dysfunction. In patients on dialysis, treatment strategies include optimizing dose of dialysis, correction of anemia with erythropoietin, and correction of hyperparathyroidism. Successful kidney transplantation may restore normal sexual function, especially in younger patients.

Work-induced changes in skeletal muscle IGF-1 and myostatin gene expression in uremia

Resistance to growth hormone (GH)-induced insulin-like growth factor-1 (IGF-1) gene expression contributes to uremic muscle wasting. Since exercise stimulates muscle IGF-1 expression independent of GH, we tested whether work overload (WO) could increase skeletal muscle IGF-1 expression in uremia and thus bypass the defective GH action. Furthermore, to provide insight into the mechanism of uremic wasting and the response to exercise we examined myostatin expression. Unilateral plantaris muscle WO was initiated in uremic and pairfed (PF) normal rats by ablation of a gastrocnemius tendon and adjoining part of this muscle with the contralateral plantaris as a control. Some rats were GH treated for 7 days. WO led to similar gains in plantaris weight in both groups and corrected the uremic muscle atrophy. GH increased plantaris IGF-1 mRNA >twofold in PF rats but the response in uremia was severely attenuated. WO increased the IGF-1 mRNA levels significantly in both uremic and PF groups, albeit less brisk in uremia; however, after 7 days IGF-1 mRNA levels were elevated similarly, >2-fold, in both groups. In the atrophied uremic plantaris muscle basal myostatin mRNA levels were increased significantly and normalized after an increase in WO suggesting a myostatin role in the wasting process. In the hypertrophied uremic left ventricle the basal myostatin mRNA levels were reduced and likely favor the cardiac hypertrophy. Together the findings provide insight into the mechanisms of skeletal muscle wasting in uremia and the hypertrophic response to exercise, and suggest that alterations in the balance between IGF-1 and myostatin play an important role in these processes.

Testosterone supplementation in aging men and women: possible impact on cardiovascular-renal disease

Treatment of aging men and women with testosterone supplements is increasing. The supplements are given to postmenopausal women mainly to improve their libido and to aging men to improve muscle mass and bone strength, to improve libido and quality of life, to prevent and treat osteoporosis, and, with the phosphodiesterase-5 inhibitors, such as sildenafil, to treat erectile dysfunction. The increased use of testosterone supplements in aging individuals has occurred despite the fact that there have been no rigorous clinical trials examining the effects of chronic testosterone on the cardiovascular-renal disease risk. Studies in humans and animals have suggested that androgens can increase blood pressure and compromise renal function. Androgens have been shown to increase tubular sodium and water reabsorption and activate various vasoconstrictor systems in the kidney, such as the renin-angiotensin system and endothelin. There is also evidence that androgens may increase oxidative stress. Furthermore, the kidney contains the enzymes necessary to produce androgens de novo. This review presents an overview of the data from human and animal studies in which the role of androgens in promoting renal and cardiovascular diseases has been investigated.