Efficacy and safety of long-acting intramuscular testosterone undecanoate in aging men: a randomised controlled study

Effect of testosterone replacement therapy on lower urinary tract symptoms: A systematic review and network meta-analysis

OBJECTIVE

In this study, we aimed to perform a network meta-analysis (NMA) to investigate the effects of different testosterone replacement therapy (TRT) administration routes on lower urinary tract symptoms (LUTS) in aging men with late-onset hypogonadism (LOH).

METHODS

A systematic search of PubMed, Embase, The Cochrane Library, CNKI, WanFang Data, and VIP was conducted to identify randomized controlled trials (RCTs) reporting data on International Prostate Symptom Score (IPSS), prostate-specific antigen (PSA) level, or prostate volume. NMA was performed, and subgroup analysis was conducted to assess the impact of TRT duration on outcomes.

RESULTS

A total of 21 RCTs involving 2453 participants were included. For pairwise meta-analysis, p values for TRT delivered by transdermal, intramuscular, and oral routes were as follows: IPSS: 0.93, 0.20, and 0.76; PSA level: 0.20, 0.27, and 0.98; prostate volume: 0.18, 0.04, and 0.16. There were no significant differences in IPSS, PSA level, or prostate volume between TRT routes. In subgroup analysis, long-term intramuscular TRT significantly decreased IPSS (p = 0.03), short-term transdermal TRT increased PSA levels (p < 0.001), and short-term intramuscular TRT increased the prostate volume (p = 0.04). Other forms of TRT showed no significant change in IPSS, PSA level, and prostate volume compared with the placebo. Indirect comparison of the three administration routes demonstrated no significant differences in IPSS, PSA level, and prostate volume. Nevertheless, surface under the cumulative ranking curve analysis indicated that intramuscular TRT had an 83% probability of being the best method for decreasing IPSS.

CONCLUSIONS

The results demonstrate that TRT does not worsen LUTS regardless of the administration route. Intramuscular TRT may be the preferred treatment for aging men with LOH and LUTS. Intramuscular TRT may be the preferred treatment for men with LOH and LUTS. Further research is warranted to validate these findings and optimize TRT management strategies.

Testosterone replacement therapy and vascular thromboembolic events: a systematic review and meta-analysis

To evaluate the relationship between testosterone replacement therapy (TRT) and arterial and/or venous thrombosis in patients with pre-treatment total testosterone (TT) <12 nmol l -1 , we performed a meta-analysis following the Population Intervention Comparison Outcome model. Population: men with TT <12 nmol l -1 or clear mention of hypogonadism in the inclusion criteria of patients; intervention: TRT; comparison: placebo or no therapy; outcomes: arterial thrombotic events (stroke, myocardial infarction [MI], upper limbs, and lower limbs), VTE (deep vein thrombosis [DVT], portal vein thrombosis, splenic thrombosis, and pulmonary embolism), and mortality. A total of 2423 abstracts were assessed for eligibility. Twenty-four studies, including 14 randomized controlled trials (RCTs), were finally included, with a total of 4027 and 310 288 hypotestosteronemic male patients, from RCTs and from observational studies, respectively. Based on RCT-derived data, TRT did not influence the risk of arterial thrombosis (odds ratio [OR] = 1.27, 95% confidence interval [CI]: 0.47-3.43, P = 0.64), stroke (OR = 1.34, 95% CI: 0.09-18.97, P = 0.83), MI (OR = 0.51, 95% CI: 0.11-2.31, P = 0.39), VTE (OR = 1.42, 95% CI: 0.22-9.03, P = 0.71), pulmonary embolism (OR = 1.38, 95% CI: 0.27-7.04, P = 0.70), and mortality (OR = 0.70, 95% CI: 0.20-2.38, P = 0.56). Meanwhile, when only observational studies are considered, a significant reduction in the risk of developing arterial thrombotic events, MI, venous thromboembolism, and mortality was observed. The risk for DVT remains uncertain, due to the paucity of RCT-based data. TRT in men with TT <12 nmol l -1 is safe from the risk of adverse cardiovascular events. Further studies specifically assessing the risk of DVT in men on TRT are needed.

An updated systematic review and meta-analysis of the effects of testosterone replacement therapy on erectile function and prostate

Introduction

Testosterone replacement therapy (TRT) is a generally accepted method treating for aging-related late-onset hypogonadism (LOH). However, the efficacy and safety of TRT remain controversial. An updated systematic review and meta-analysis aimed to determine the effectiveness and security of TRT treating for LOH.

Methods

Randomized controlled trials (RCTs) of TRT for LOH were searched in the databases of Pubmed, Embase, Clinicaltrials.gov and Cochrane from 1990 to 2023 and an updated meta-analysis was conducted.

Results

The results of 28 RCTs involving 3461 patients were included and scrutinized in this analysis. Among these, 11 RCTs were of long-term duration (≥12 months), while 18 RCTs were short-term studies (<12 months) comparing TRT with a placebo. TRT modalities comprised injection, oral administration, and transdermal administration. International Index of Erectile Function (IIEF) (Weighted Mean difference (WMD) 3.26; 95%; 95% confidence interval (CI) 1.65-4.88; P<0.0001) was obviously improved in the TRT group. International Prostate Symptom Score (IPSS) (WMD 0.00; 95% CI -0.45-0.45; P=1.0), Prostate Volume (PV) (WMD 0.38; 95% CI -0.64-1.41; P=0.46), Maximum Flow Rate (Qmax) (WMD 1.86; 95% CI -0.98-4.69; P=0.20), Postvoid Residual Urine Volume (PVR) (WMD 3.20; 95% CI -5.87-12.28; P=0.49) and Prostate-Specific Antigen (PSA) (WMD 0.08; 95% CI -0.00-0.17; P=0.06) were not significantly statistical between two groups.

Conclusion

This meta-analysis reveals that TRT could improve the IIEF score of hypogonadal men without detriment to the IPSS score, PV, Qmax, PVR and PSA regardless of the administration method or duration of treatment.The meta-analysis was registered at PROSPERO (CRD42023413434).

Testosterone replacement in men with sexual dysfunction

BACKGROUND

Clinical practice guidelines recommend testosterone replacement therapy (TRT) for men with sexual dysfunction and testosterone deficiency. However, TRT is commonly promoted in men without testosterone deficiency and existing trials often do not clearly report participants' testosterone levels or testosterone-related symptoms. This review assesses the potential benefits and harms of TRT in men presenting with complaints of sexual dysfunction.

OBJECTIVES

To assess the effects of testosterone replacement therapy compared to placebo or other medical treatments in men with sexual dysfunction.

SEARCH METHODS

We performed a comprehensive search of CENTRAL (the Cochrane Library), MEDLINE, EMBASE, and the trials registries ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform, with no restrictions on language of publication or publication status, up to 29 August 2023.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in men (40 years or over) with sexual dysfunction. We excluded men with primary or secondary hypogonadism. We compared testosterone or testosterone with phosphodiesterase-5 inhibitors (PDEI5I) to placebo or PDE5I alone.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the literature, assessed the risk of bias, extracted data, and rated the certainty of evidence (CoE) according to GRADE using a minimally contextualized approach. We performed statistical analyses using a random-effects model and interpreted them according to standard Cochrane methodology. Predefined primary outcomes were self-reported erectile dysfunction assessed by a validated instrument, sexual quality of life assessed by a validated instrument, and cardiovascular mortality. Secondary outcomes were treatment withdrawal due to adverse events, prostate-related events, and lower urinary tract symptoms (LUTS). We distinguished between short-term (up to 12 months) and long-term (> 12 months) outcomes.

MAIN RESULTS

We identified 43 studies with 11,419 randomized participants across three comparisons: testosterone versus placebo, testosterone versus PDE5I, and testosterone with PDE5I versus PDE5I alone. This abstract focuses on the most relevant comparison of testosterone versus placebo. Testosterone versus placebo (up to 12 months) Based on a predefined sensitivity analysis of studies at low risk of bias, and an analysis combing data from the similar International Index of Erectile Function (IIEF-EF) and IIEF-5 instruments, TRT likely results in little to no difference in erectile function assessed with the IIEF-EF (mean difference (MD) 2.37, 95% confidence interval (CI) 1.67 to 3.08; I² = 0%; 6 RCTs, 2016 participants; moderate CoE) on a scale from 6 to 30 with larger values reflecting better erectile function. We assumed a minimal clinically important difference (MCID) of greater than or equal to 4. TRT likely results in little to no change in sexual quality of life assessed with the Aging Males' Symptoms scale (MD -2.31, 95% CI -3.63 to -1.00; I² = 0%; 5 RCTs, 1030 participants; moderate CoE) on a scale from 17 to 85 with larger values reflecting worse sexual quality of life. We assumed a MCID of greater than or equal to 10. TRT also likely results in little to no difference in cardiovascular mortality (risk ratio (RR) 0.83, 95% CI 0.21 to 3.26; I² = 0%; 10 RCTs, 3525 participants; moderate CoE). Based on two cardiovascular deaths in the placebo group and an assumed MCID of 3%, this would correspond to no additional deaths per 1000 men (95% CI 1 fewer to 4 more). TRT also likely results in little to no difference in treatment withdrawal due to adverse events, prostate-related events, or LUTS. Testosterone versus placebo (later than 12 months) We are very uncertain about the longer-term effects of TRT on erectile dysfunction assessed with the IIEF-EF (MD 4.20, 95% CI -2.03 to 10.43; 1 study, 42 participants; very low CoE). We did not find studies reporting on sexual quality of life or cardiovascular mortality. We are very uncertain about the effect of testosterone on treatment withdrawal due to adverse events. We found no studies reporting on prostate-related events or LUTS.

AUTHORS' CONCLUSIONS

In the short term, TRT probably has little to no effect on erectile function, sexual quality of life, or cardiovascular mortality compared to a placebo. It likely results in little to no difference in treatment withdrawals due to adverse events, prostate-related events, or LUTS. In the long term, we are very uncertain about the effects of TRT on erectile function when compared to placebo; we did not find data on its effects on sexual quality of life or cardiovascular mortality. The certainty of evidence ranged from moderate (signaling that we are confident that the reported effect size is likely to be close to the true effect) to very low (indicating that the true effect is likely to be substantially different). The findings of this review should help to inform future guidelines and clinical decision-making at the point of care.

Cardiovascular Outcomes of Hypogonadal Men Receiving Testosterone Replacement Therapy: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To investigate the impact of testosterone replacement therapy (TRT) on cardiovascular outcomes in hypogonadal men.

METHODS

A meta-analysis of 26 randomized controlled trials involving 10 941 participants was conducted. Various clinical outcomes, including all-cause mortality, cardiovascular-related mortality, myocardial infarction, stroke, congestive heart failure, atrial fibrillation, pulmonary embolism, and venous thrombosis, were assessed.

RESULTS

No statistically significant differences were observed between the TRT group and the control group in terms of these clinical outcomes. Sensitivity analysis and publication bias assessment supported the robustness of the findings. Meta-regression analysis found no significant associations between clinical outcomes and potential covariates, including age, diabetes, hypertension, dyslipidemia, and smoking.

DISCUSSION

Previous research on TRT and cardiovascular events, with comparisons to studies like the Testosterone Trials and the studies conducted by Vigen et al, Finkle et al, Layton et al, and Wallis et al, is provided. The significance of the systematic review and meta-analysis approach is emphasized, particularly its exclusive focus on hypogonadal patients.

CONCLUSION

This study offers reassurance that TRT does not increase mortality risk or worsen cardiovascular outcomes in hypogonadal men. However, further research, especially long-term studies involving diverse populations, is essential to strengthen the evidence base and broaden the applicability of these findings.

The Roles of Androgens in Humans: Biology, Metabolic Regulation and Health

Androgens are an important and diverse group of steroid hormone molecular species. They play varied functional roles, such as the control of metabolic energy fate and partition, the maintenance of skeletal and body protein and integrity and the development of brain capabilities and behavioral setup (including those factors defining maleness). In addition, androgens are the precursors of estrogens, with which they share an extensive control of the reproductive mechanisms (in both sexes). In this review, the types of androgens, their functions and signaling are tabulated and described, including some less-known functions. The close interrelationship between corticosteroids and androgens is also analyzed, centered in the adrenal cortex, together with the main feedback control systems of the hypothalamic-hypophysis-gonads axis, and its modulation by the metabolic environment, sex, age and health. Testosterone (T) is singled out because of its high synthesis rate and turnover, but also because age-related hypogonadism is a key signal for the biologically planned early obsolescence of men, and the delayed onset of a faster rate of functional losses in women after menopause. The close collaboration of T with estradiol (E2) active in the maintenance of body metabolic systems is also presented Their parallel insufficiency has been directly related to the ravages of senescence and the metabolic syndrome constellation of disorders. The clinical use of T to correct hypoandrogenism helps maintain the functionality of core metabolism, limiting excess fat deposition, sarcopenia and cognoscitive frailty (part of these effects are due to the E2 generated from T). The effectiveness of using lipophilic T esters for T replacement treatments is analyzed in depth, and the main problems derived from their application are discussed.

Occurrence of pulmonary oil microembolism (POME) with intramuscular testosterone undecanoate injection: literature review

Testosterone undecanoate injections (TU), an oil-based depot, is a universal hormonal-based treatment which has been associated with pulmonary oil microembolism (POME). However, the rate of POME during routine intramuscular (IM) TU injection is unknown. Here, we conduct a peer-reviewed literature review investigating POME incidents in the setting of TU injections. A total of 48 articles were selected in the literature review, which included 29 studies that used TU and reported its effects. Relatively few POME cases were reported across multiple published studies, including those that focused particularly on the occurrence rate of POME while administrating IM TU. Of the 29 individual studies, which included 7 978 patients, eight studies reported a total of 88 incidence of POME cases or cough. This included episodes of cough that were not originally declared as POME. One post market review reported 223 cases per 3,107,652 injections. When POME did occur, almost all cases resolved spontaneously within 60 min without intervention. Overall, POME was observed to be rare.

Glucose metabolic disorder in Klinefelter syndrome: a retrospective analysis in a single Chinese hospital and literature review

BACKGROUND

We aimed to investigate the clinical characteristics and islet β-cell function in patients with Klinefelter syndrome (KS) and hyperglycemia.

METHODS

This is a retrospective study. In total, 22 patients diagnosed with KS were identified from the electronic medical record system, including 9 patients with hyperglycemia (total patients with hyperglycemia, THG-KS group) and 5 hyperglycemic KS patients with oral glucose tolerance test (OGTT) results (HG-KS group). An additional 5 subjects with hyperglycemia and 5 normal glucose tolerance (NGT) subjects matched based on body mass index were included as the HG group and NGT group, respectively. Data from clinical and laboratory examinations were collected. We further performed a literature review of KS and hyperglycemia.

RESULTS

We found that KS patients developed abnormal glucose metabolism earlier in life than those without KS, and the median age was 17 years, ranging from 10 years to 19 years. Six of 17 (35.3%) patients were diagnosed with diabetes mellitus and 3 of 17 (17.6%) patients were diagnosed with prediabetes. Among 10 patients with both fasting blood glucose and insulin results recorded, there were 8 out of 17 (47.1%) KS patients had insulin resistance. The prevalence of hypertension and dyslipidemia was higher in patients with hyperglycemia and KS than in patients with NGT KS. Compared with the HG group, insulin sensitivity levels were lower in HG-KS group, whereas homeostasis model assessment of β-cell function levels (p = 0.047) were significantly, indicating higher insulin secretion levels in the HG-KS group.

CONCLUSIONS

KS patients develop hyperglycemia earlier in life than those without KS and show lower insulin sensitivity and higher insulin secretion. These patients also have a higher prevalence of other metabolic diseases and may have different frequencies of developing KS-related symptoms.

Patient-reported outcomes and biochemical alterations during hormonal therapy in men with hypogonadotropic hypogonadism who have finished infertility treatment

Male hypogonadotropic hypogonadism (MHH) is effectively treated by gonadotropins with a high rate of ejaculate sperm and paternity; however, there is no information regarding the appropriate management, including patient-reported outcomes (PROs), of men with MHH who have finished infertility treatment. To compare health-related quality of life, erectile function and biochemical alterations in men with MHH who were treated with testosterone replacement therapy (TRT) or human chorionic gonadotropin (hCG). Twenty-six MHH patients (mean age: 34 years) who needed to improve their androgen deficiency symptoms underwent either hCG therapy (n = 16, started with self-injection of 2,000-7,500 IU per week) or TRT (n = 10, testosterone enanthate 250 mg every 3 weeks). The 36-item Short Form Health Survey (SF-36) questionnaire, five-item International Index of Erectile Function (IIEF-5) and hormonal and biochemical analyses were assessed every 3 months. Changes and comparison of each treatment regarding these parameters were analyzed. Both hCG and TRT significantly improved all domains of the SF-36, except for bodily pain and social functioning. hCG significantly improved the general and mental health domains compared with TRT. Significant improvements in IIEF-5 were observed with both treatments, showing significant improvement with hCG compared to TRT. TRT caused progressive testicular atrophy. There were significant decreases in waist circumference and triglycerides in both treatment groups and significant elevations in prostate-specific antigen and hematocrit. Both hCG and TRT are effective and safe, with preferable PROs by hCG, for treating androgen deficiency in men with MHH who do not need infertility treatment.

Long-term testosterone undecanoate replacement therapy: Impact of ethnicity

BACKGROUND

Testosterone replacement therapy (TRT) is indicated for symptomatic male hypogonadism. However, the safety and efficacy profiles across different ethnicities for long-term TRT remain unclear.

OBJECTIVE

To measure the impact of ethnicity on various biochemical parameters following testosterone undecanoate (TU) replacement.

METHOD

A retrospective analysis of 50 male patients treated with TU from 2006 to 2017 in a large secondary care centre was performed. Changes in total testosterone, PSA, haematocrit, haemoglobin, total cholesterol and low-density lipoprotein (LDL) over eight years of treatment were analysed. Wilcoxon rank sum test was used to assess differences in these parameters between Caucasians and South Asians.

RESULTS

Thirty-one Caucasians (age: median (IQR) 55.0 years (49.0-68.0); total duration of follow-up 6.1 years (2.9-9.3)) and 19 South Asians (age: median (IQR) 52.0 years (38.0-69.0); duration of follow-up 6.5 years (1.3-8.4)) were treated with TU during the study period. There was no significant difference in total testosterone levels between the two ethnicities. We noted a higher free and bioavailable testosterone in South Asians than Caucasians, albeit within their reference range. PSA was higher in Caucasians than South Asians at two and eight years of TU therapy. After one year of TRT, haematocrit was higher in South Asians than Caucasians at one year, whereas LDL and total cholesterol were significantly higher in Caucasians than South Asians.

CONCLUSIONS

Caucasians have a tendency towards increased PSA, total cholesterol and LDL compared with South Asians with TU replacement therapy. There is a higher increment of haematocrit in South Asians following one year of TU replacement therapy. All biochemical changes following TRT were within the respective reference ranges suggesting no apparent risk of prostate cancer and venous thromboembolism.

The effects of testosterone on bone health in males with testosterone deficiency: a systematic review and meta-analysis

BACKGROUND

Testosterone deficiency (TD) may induce a series of clinical symptoms. Studies have shown that testosterone supplementation may prevent these unfavourable symptoms and improve patients' quality of life. Given the conflicting findings across studies, this systematic review aims to evaluate the effects and risks associated with testosterone supplementation in middle-aged or aging males with TD.

METHODS

Electronic databases (MEDLINE, EMBASE, PubMed, and Cochrane. Library were searched to December 2019. The risk of bias of individual included studies and the quality of the aggregate evidence were assessed using the GRADE approach. Our primary outcome was bone mineral density (BMD). Meta-analyses were performed. This systematic review was reported according to the PRISMA statement.

RESULTS

A total of 52 randomized controlled trials (RCTs) were included. When compared with placebo, testosterone supplementation did not increase total BMD (short-term: 1081 participants, MD - 0.01 g/cm², 95% CI - 0.02 g/cm² to 0.01 g/cm²; long-term: 156 participants, MD 0.04 g/cm², 95% CI - 0.07 g/cm² to 0.14 g/cm²), lumbar spine, hip, or femur neck BMD. Furthermore, testosterone supplementation did not decrease the risk of falling or fracture. Lastly, it was found that testosterone supplementation did not increase the risk of cardiovascular events (1374 participants, RR 1.28, 95% CI 0.62 to 2.64), all-cause mortality (729 participants, RR 0.55, 95% CI 0.29 to 1.04), or prostatic events. However, testosterone supplementation may improve sexual function and quality of life (1328 participants, MD -1.32, 95% CI - 2.11 to - 0.52).

CONCLUSIONS

The effect of testosterone supplementation on BMD and the risk of falls or fracture remains inconclusive. However, supplementation may benefit patients in the areas of sexual function and quality of life without increasing the risk of cardiovascular events, all-cause mortality, or prostatic events. RCTs with a longer follow-up period are still required.

TRIAL REGISTRATION

We registered our protocol in PROSPERO (CRD42018109738).

Hypogonadism and its treatment following ischaemic stroke in men with type 2 diabetes mellitus

Premature mortality in Russia is a major socio-economic problem, especially from acute cerebrovascular diseases which constitute 21.4% of the total mortality and is a considerable contributor to chronic disability. Risk of vascular catastrophe is higher in males than females, thought, in part, due to anti-atherosclerotic effects of oestrogens in females whilst an associated age-related deficiency of testosterone is observed in men. Clinical symptoms such as high blood pressure, changes in lipid profile, insulin resistance, obesity, and blood coagulation factors often accompany declining testosterone in males and reduced total testosterone is considered a cardiovascular risk factor. In the present study, the prevalence of hypogonadism in men who had suffered ischaemic stroke was evaluated along with the efficacy of testosterone undecanoate injections (TU) in patients with testosterone deficiency and type-2 diabetes (T2DM) in the acute phase of hemispheric ischaemic stroke. Hypogonadism was present in 66.3% of patients with ischaemic stroke, 50% with T2DM, and 26.3% without T2DM, respectively. TU treatment, at both the 2 and 5-year observation points, demonstrated significant improvements in biochemical, physical, and mental parameters. This supports that testosterone deficiency is a contributing factor in ischaemic events and that long-term testosterone therapy could play an important role in patient recovery.

Late-onset hypogonadism: Prostate safety

BACKGROUND

There have always been concerns regarding testosterone replacement therapy and prostate safety because of the central role of testosterone in prostate tissue. Even though there is a body of evidence supporting that the benefits of testosterone replacement therapy outbalance the risks of prostate disease, this matter is still debatable and represents a common concern among testosterone prescribers.

OBJECTIVES

The aim of this article was to review the influence of testosterone on prostate pathophysiology and discuss the potential impact of testosterone replacement therapy on the most common prostate pathologies, including benign prostatic hyperplasia and prostate cancer.

MATERIALS AND METHODS

We have performed an extensive PubMed review of the literature examining the effects of testosterone replacement therapy on the prostate and its most common affections, especially in terms of safety.

RESULTS

Testosterone replacement therapy has been shown to improve components of metabolic syndrome and decrease prostate inflammation, which is related to the worsening of lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia. Studies evaluating the link between testosterone replacement therapy and benign prostatic hyperplasia/LUTS have mostly demonstrated no change in symptom scores and even some benefits. There are a significant number of studies demonstrating the safety of testosterone replacement therapy in individuals with late-onset hypogonadism and a history of prostate cancer. The most recently published guidelines have already acknowledged this fact and do not recommend against T treatment in this population, particularly in non-high-risk disease.

CONCLUSION

Testosterone replacement therapy could be considered for most men with late-onset hypogonadism regardless of their history of prostate disease. However, a discussion about the risks and benefits of testosterone replacement therapy is always advised, especially in men with prostate cancer. Appropriate monitoring is mandatory.

Efficacy and Safety of Testosterone Treatment in Men: An Evidence Report for a Clinical Practice Guideline by the American College of Physicians

BACKGROUND

Testosterone treatment rates in adult men have increased in the United States over the past 2 decades.

PURPOSE

To assess the benefits and harms of testosterone treatment for men without underlying organic causes of hypogonadism.

DATA SOURCES

English-language searches of multiple electronic databases (January 1980 to May 2019) and reference lists from systematic reviews.

STUDY SELECTION

38 randomized controlled trials (RCTs) of at least 6 months' duration that evaluated transdermal or intramuscular testosterone therapies versus placebo or no treatment and reported prespecified patient-centered outcomes, as well as 20 long-term observational studies, U.S. Food and Drug Administration review data, and product labels that reported harms information.

DATA EXTRACTION

Data extraction by a single investigator was confirmed by a second, 2 investigators assessed risk of bias, and evidence certainty was determined by consensus.

DATA SYNTHESIS

Studies enrolled mostly older men who varied in age, symptoms, and testosterone eligibility criteria. Testosterone therapy improved sexual functioning and quality of life in men with low testosterone levels, although effect sizes were small (low- to moderate-certainty evidence). Testosterone therapy had little to no effect on physical functioning, depressive symptoms, energy and vitality, or cognition. Harms evidence reported in trials was judged to be insufficient or of low certainty for most harm outcomes. No trials were powered to assess cardiovascular events or prostate cancer, and trials often excluded men at increased risk for these conditions. Observational studies were limited by confounding by indication and contraindication.

LIMITATION

Few trials exceeded a 1-year duration, minimum important outcome differences were often not established or reported, RCTs were not powered to assess important harms, few data were available in men aged 18 to 50 years, definitions of low testosterone varied, and study entry criteria varied.

CONCLUSION

In older men with low testosterone levels without well-established medical conditions known to cause hypogonadism, testosterone therapy may provide small improvements in sexual functioning and quality of life but little to no benefit for other common symptoms of aging. Long-term efficacy and safety are unknown.

PRIMARY FUNDING SOURCE

American College of Physicians. (PROSPERO: CRD42018096585).

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Klinefelter Syndrome and Diabetes

PURPOSE OF REVIEW

Klinefelter syndrome (KS) is associated with increased insulin resistance and high rates of type 2 diabetes (T2DM). Our aim was to review what is known about the prevalence of diabetes in men with KS, potential mechanisms underlying the observed metabolic phenotype, and the data that are available to guide treatment decisions.

RECENT FINDINGS

The increased prevalence of T2DM seen in men with KS appears to be the result of multiple mechanisms including increased truncal adiposity and socioeconomic disadvantages, but it is likely not a direct consequence of hypogonadism alone. No randomized trials have been conducted to evaluate the impact of testosterone replacement therapy on T2DM in men with KS, but observational data suggest that testosterone replacement is not associated with lower rates of diabetes or improved glycemic control. Metabolic derangements are common in KS, but treatment strategies specific to this population are lacking. Early lifestyle and dietary interventions are likely important. Additional research is needed to dissect the complex interaction between genotype and metabolic phenotype. Collaboration between academic centers caring for men with KS is needed to facilitate the development of evidence-based clinical practice guidelines, which would inform optimal screening and treatment strategies for this patient population.

Pharmacokinetics, safety, and patient acceptability of subcutaneous versus intramuscular testosterone injection for gender-affirming therapy: A pilot study

PURPOSE

Results of a study comparing testosterone exposure and tolerability with subcutaneous versus i.m. administration are presented.

METHODS

In a prospective, open-label, crossover study, adult participants already on stable i.m. testosterone gender-affirming therapy self-injected testosterone cypionate or enanthate i.m. for 3 weeks followed by subcutaneous injections for 8 weeks. Trough serum testosterone concentrations were determined weekly, and serial total serum testosterone (TST) concentrations were determined on postinjection days 1, 3, and 5 of weeks 3 and 11. Hemoglobin and alanine transaminase (ALT) levels were measured at week 3 (the first visit), with repeat measurements at week 11 (the final visit). The dose-normalized area under the time-concentration curve (AUC) was calculated during weeks 3 and 11.

RESULTS

Fourteen transgender males (mean age, 30 ± 10 years) participated in the study. The mean hemoglobin values at the first and final visits were 160 ± 9 and 153 ± 9 g/L, respectively (p > 0.05); the mean ALT values were 18 ± 6 and 21 ± 10 IU/L (p > 0.05). Total testosterone exposure was comparable with subcutaneous versus i.m. injection (mean AUC, 1.7 ± 0.6 nmol·days/L/mg versus 1.9 ± 0.6 nmol·days/L/mg; p > 0.05). Information collected via weekly questionnaires indicated that the subcutaneous route was more tolerable, with lower self-reported scores for preinjection anxiety, pain during injection, and postinjection pain.

CONCLUSION

The subcutaneous route for the injection of testosterone was well tolerated and appeared to be as effective as i.m. injection in delivering equivalent TST levels, although there was wide intrapatient and interpatient variability.

Effectiveness and tolerability of parenteral testosterone undecanoate: a post-marketing surveillance study

This observational post-marketing study of parenteral testosterone undecanoate (TU) in a non-selected population aimed to: examine the effectiveness of TU as treatment of hypogonadism; record adverse drug reactions (ADR) quantitatively particularly regarding polycythemia, prostate safety and cardiovascular-related metabolic risk factors; and verify whether recommended injection intervals apply to routine clinical practice. Eight hundred and seventy subjects from 259 outpatient units scheduled to visit the clinic six times were included. Effectiveness and tolerability of TU administration were assessed on a 4-point scale. Body weight, waist girth, blood pressure, hemoglobin levels, hematocrit, prostate-specific antigen (PSA), and digital rectal prostate examination were assessed. Over 90% of subjects completed the observational duration of 52.8 ± 9.7 weeks (mean ± SD) and 56% judged effectiveness as very good, 30.8% as good. 63.1% judged tolerability as very good, and 24.4% as good. No adverse effects on indicators of cardiovascular risk were observed. Polycythemia occurred in one subject and a supranormal hematocrit in one subject. Four subjects developed supranormal PSA levels. Prostate carcinoma was found in one subject, one subject had recurrence of a previously surgically treated prostate carcinoma, and the other two showed no indication of malignancy. Parenteral TU is safe, effective, and well-tolerated in clinical practice proving a good therapeutic option for hypogonadism.

Effects of testosterone administration on liver structure and function in aging rats

Aging males have a decrease in testosterone levels, by which the testosterone treatment may influence in a negatively fashion the liver.

AIM

This study aimed to analyze the effects of aging with or without testosterone administration on the liver components of animals.

METHODS

Wistar rats were divided into three groups: 20 months' group (G20), 24 months' group (G24), group treated with testosterone for 16 weeks (GT). All groups were sacrificed at 24 months except for G20 that was sacrificed at 20 months.

RESULTS

Aging and testosterone treatment alters the body weight (BW), liver weight (LW) and relative liver weight. Besides, testosterone increased the mitogen capacity of hepatocytes. Nonetheless, we reinforce the negative effects of testosterone on old animals' liver as chronic hepatic congestion and/or cholestasis. In addition, we observed that testosterone plays an important role on hepatic glycogen stores.

CONCLUSIONS

Our study showed many implications for the knowledge about the effects of aging with or without testosterone administration on old animals' liver.

Adult-onset hypogonadism: evaluation and role of testosterone replacement therapy

Testosterone deficiency (TD) has become a growing concern in the field of men’s sexual health, with an increasing number of men presenting for evaluation of this condition. Given the increasing demand for testosterone replacement therapy (TRT), a panel of experts met in August of 2015 to discuss the treatment of men who present for evaluation in the setting of low or normal gonadotropin levels and the associated signs and symptoms of hypogonadism. This constellation of factors can be associated with elements of both primary and secondary hypogonadism. Because this syndrome commonly occurs in men who are middle-aged and older, it was termed adult-onset hypogonadism (AOH). AOH can be defined by the following elements: low levels of testosterone, associated signs and symptoms of hypogonadism, and low or normal gonadotropin levels. Although there are significant benefits of TRT for patients with AOH, candidates also need to understand the potential risks. Patients undergoing TRT will need to be monitored regularly because there are potential complications that can develop with long-term use. This review is aimed at providing a deeper understanding of AOH, discussing the benefits and risks of TRT, and outlining each modality of TRT in use for AOH.

Association between exogenous testosterone and cardiovascular events: an overview of systematic reviews

Given the conflicting evidence regarding the association between exogenous testosterone and cardiovascular events, we systematically assessed published systematic reviews for evidence of the association between exogenous testosterone and cardiovascular events. We searched PubMed, MEDLINE, Embase, Cochrane Collaboration Clinical Trials, ClinicalTrials.gov, and the US Food and Drug Administration website for systematic reviews of randomised controlled trials published up to July 19, 2016. Two independent reviewers screened 954 full texts from 29 335 abstracts to identify systematic reviews of randomised controlled trials in which the cardiovascular effects of exogenous testosterone on men aged 18 years or older were examined. We extracted data for study characteristics, analytic methods, and key findings, and applied the AMSTAR (A Measurement Tool to Assess Systematic Reviews) checklist to assess methodological quality of each review. Our primary outcome measure was the direction and magnitude of association between exogenous testosterone and cardiovascular events. We identified seven reviews and meta-analyses, which had substantial clinical heterogeneity, differing statistical methods, and variable methodological quality and quality of data abstraction. AMSTAR scores ranged from 3 to 9 out of 11. Six systematic reviews that each included a meta-analysis showed no significant association between exogenous testosterone and cardiovascular events, with summary estimates ranging from 1·07 to 1·82 and imprecise confidence intervals. Two of these six meta-analyses showed increased risk in subgroup analyses of oral testosterone and men aged 65 years or older during their first treatment year. One meta-analysis showed a significant association between exogenous testosterone and cardiovascular events, in men aged 18 years or older generally, with a summary estimate of 1·54 (95% CI 1·09-2·18). Our optimal information size analysis showed that any randomised controlled trial aiming to detect a true difference in cardiovascular risk between treatment groups receiving exogenous testosterone and their controls (with a two-sided p value of 0·05 and a power of 80%) would require at least 17 664 participants in each trial group. Therefore, given the challenge of adequately powering clinical trials for rare outcomes, rigorous observational studies are needed to clarify the association between testosterone-replacement therapy and major adverse cardiovascular outcomes.

Androgen receptor transcriptionally regulates μ-opioid receptor expression in rat trigeminal ganglia

The involvement of testosterone in pain, inflammation, and analgesia has been reported, but the role of androgen receptor (AR), a steroid receptor for testosterone, is not well understood. We have previously shown that peripheral inflammation upregulates μ-opioid receptor (MOR) in rat trigeminal ganglia (TG) in a testosterone-dependent manner. In this study, we hypothesized that testosterone regulates MOR expression via transcriptional activities of AR in TG. We first examined whether AR is co-expressed with MOR in TG neurons. Our immunohistochemical experiment revealed that AR staining is detected in neurons of all sizes in TG and that a subset of AR is expressed in MOR as well as in TRPV1-positive neurons. We identified the promoter region of the rat MOR gene contains putative AR binding sites. Using chromatin immunoprecipitation assay, we demonstrated that AR directly binds to these sites in TG extracts. We confirmed with luciferase reporter assay that AR activated the MOR promoter in response to androgens in a human neuroblastoma cell line (5H-5YSY). These data demonstrated that AR functions as a transcriptional regulator of the MOR gene activity. Finally, we showed that flutamide, a specific AR antagonist, prevents complete Freund's adjuvant (CFA)-induced upregulation of MOR mRNA in TG, and that flutamide dose-dependently blocks the efficacy of DAMGO, a specific MOR agonist, on CFA-induced mechanical hypersensitivity. Our results expand the knowledge regarding the role of androgens and their receptor in pain and analgesia and have important clinical implications, particularly for inflammatory pain patients with low or compromised plasma testosterone levels.

Improved Lower Urinary Tract Symptoms Associated With Testosterone Replacement Therapy in Japanese Men With Late-Onset Hypogonadism

This study aimed to investigate the effects of testosterone replacement therapy (TRT) on lower urinary tract symptoms (LUTS) in men with late-onset hypogonadism (LOH) and to identify parameters predicting the efficacy of TRT in improving LUTS. This study included 60 consecutive Japanese men who were diagnosed with LOH and subsequently received TRT between January 2009 and December 2014. In this series, 250 mg of testosterone was injected intramuscularly every 3 or 4 weeks in all patients. The following parameters were retrospectively reviewed: body mass index (BMI), Aging Male Symptom (AMS) score, International Prostate Symptom Score (IPSS), International Index of Erectile Function-5 (IIEF-5) score, residual urine volume, prostate volume, serum levels of the prostate-specific antigen (PSA), and total- and free-testosterone levels before and 6 months after TRT. No significant differences were observed in BMI, residual urine volume, or prostate volume between surveys before and after TRT. The AMS score, IPSS, and IIEF-5 score were significantly improved and significant increases were noted in the serum levels of PSA and total- and free-testosterone levels after TRT. An analysis of IPSS subscores documented the significant improvement in storage symptom scores, but not in voiding symptom scores after TRT. Multivariate analyses of parameters assessed in this study identified the pretreatment AMS score, posttreatment IIEF-5 score, and prostate volume as independent predictors of improvements in IPSS following TRT. This study revealed that TRT appeared to have considerable therapeutic effects on LUTS, particularly on storage symptoms, in men with LOH.

THERAPY OF ENDOCRINE DISEASE: Testosterone supplementation and body composition: results from a meta-analysis study

OBJECTIVE

The role of testosterone (T) in regulating body composition is conflicting. Thus, our goal is to meta-analyse the effects of T supplementation (TS) on body composition and metabolic outcomes.

METHODS

All randomized controlled trials (RCTs) comparing the effect of TS on different endpoints were considered.

RESULTS

Overall, 59 trials were included in the study enrolling 3029 and 2049 patients in TS and control groups respectively. TS was associated with any significant modification in body weight, waist circumference and BMI. Conversely, TS was associated with a significant reduction in fat and with an increase in lean mass as well as with a reduction of fasting glycaemia and insulin resistance. The effect on fasting glycaemia was even higher in younger individuals and in those with metabolic diseases. When only RCTs enrolling hypogonadal (total T <12  mol/l) subjects were considered, a reduction of total cholesterol as well as triglyceride (TGs) levels were also detected. Conversely, an improvement in HDL cholesterol levels as well as in both systolic and diastolic blood pressure was not observed.

CONCLUSION

Our data suggest that TS is able to improve body composition and glycometabolic profile particularly in younger subjects and in those with metabolic disturbances. Specifically designed studies are urgently needed to confirm this point.

Effects of Testosterone Replacement Therapy on Lower Urinary Tract Symptoms: A Systematic Review and Meta-analysis

CONTEXT

There is a potential risk that testosterone replacement therapy (TRT) may exacerbate lower urinary tract symptoms (LUTS) among aging men with late-onset hypogonadism (LOH) because of testosterone's growth-promoting effects on the prostate.

OBJECTIVE

To compare the change in LUTS severity as assessed using the International Prostate Symptom Score (IPSS) between men receiving TRT versus placebo for the treatment of LOH.

EVIDENCE ACQUISITION

Systematic search of MEDLINE, Embase, ClinicalTrials.gov, and The Cochrane Library for randomized controlled trials of TRT for LOH published between January 1992 and September 2015. Studies were eligible for inclusion if they were a randomized control trial, used TRT, and assessed LUTS outcomes using the IPSS. Estimates were pooled using random effects meta-analysis. Differences by study-level characteristics were estimated using meta-regression.

EVIDENCE SYNTHESIS

Data were extracted from 14 trials involving 2029 participants. The average age was 64.5 yr and the average follow-up was 34.4 mo. Seven studies used topical, five used injectable, and two used oral testosterone. There was no statistically significant difference in pooled changes in IPSS from baseline to follow up in men treated with TRT compared with those receiving placebo (-0.41 points [95% confidence interval: -0.89 to 0.07; I(2)=0%, p=0.28] vs. 0.12 points [95% confidence interval: -0.32 to 0.55; I(2)=0%, p=0.81], between-group difference p>0.05). No between-group differences were noted in subanalyses that controlled for potential confounders such as type of testosterone, change in testosterone, aging male symptom scale, or prostate-specific antigen levels (p>0.05 for all comparisons).

CONCLUSIONS

In this meta-analysis of 14 clinical trials of TRT for LOH, the change in IPSS was similar among men receiving TRT versus placebo, suggesting that TRT treatment does not worsen LUTS among men with LOH.

PATIENT SUMMARY

In this analysis of 14 clinical trials, testosterone replacement therapy did not worsen lower urinary tract symptoms among men being treated for late-onset hypogonadism.

Obesity and late-onset hypogonadism

Obesity and male hypogonadism (HG) are often associated, as demonstrated in all cross-sectional studies. Prospective studies have indicated that i) having HG at baseline increases the risk of visceral obesity (and metabolic syndrome) and that ii) obesity induces incident HG. Hence, there is a bidirectional relationship between the two conditions. This is the main topic of this review, along with some pathogenic considerations. Meta-analysis of intervention studies indicates that treating obesity is a very efficient treatment for obesity-induced HG. The mechanism by which obesity induces HG has not yet been completely understood, but dietary-induced hypothalamic inflammation, along with a decreased GnRH release, is plausible. Among patients seeking medical care for obesity, the proportion of HG is relatively high. The prevalence of obesity among patients referring for sexual dysfunction is also elevated. Hence, in symptomatic, obese, hypogonadal subjects, testosterone supplementation (TS) can be considered. Whereas long-term uncontrolled register studies suggest that TS could decrease weight, analysis of controlled studies only support a parallel increase in lean mass and decrease in fat mass, with a resulting null effect on weight. Considering that T induces an increase in muscle mass, it is conceivable that the amount of activity obese people can undertake after TS will increase, allowing a closer adherence to physical exercise programs. Some studies, here meta-analyzed, support this concept.

Critical Update of the 2010 Endocrine Society Clinical Practice Guidelines for Male Hypogonadism: A Systematic Analysis

"Testosterone Therapy in Men With Androgen Deficiency Syndromes: An Endocrine Society Clinical Practice Guideline" (Guidelines), published in 2010, serves as an important guide for the treatment of hypogonadal men. Using the Guidelines as a basis, we searched for the most recent level 1 evidence that continues to support the recommendations or provide an impetus to modify all or some of them. We performed a systematic analysis with a PubMed query from January 1, 2010, through March 2, 2015, using the following key words: testosterone/deficiency, testosterone/therapeutic use, cardiovascular, morbidity, mortality, screening, sexual function, lower urinary tract symptoms, obstructive sleep apnea, prostate cancer, fertility, bone mineral density, osteoporosis, quality of life, cognitive, erectile dysfunction, and adverse effects. We identified 17 trials representing level 1 evidence that specifically addressed recommendations made in the Guidelines. Trials examining outcomes of testosterone replacement therapy in men with severe lower urinary tract symptoms and untreated obstructive sleep apnea were identified, potentially refuting the current dogma against treatment in the setting of these conditions. Hypogonadal men with type 2 diabetes mellitus and metabolic syndrome were examined in several trials, demonstrating the beneficial effects of therapy on sexual function and insulin sensitivity. Several trials served as reinforcing evidence for the beneficial effects of testosterone therapy on osteoporosis, muscle strength, and symptoms of frailty. As in the Guidelines, inconsistent effects on quality of life, well-being, and erectile function were also noted in publications. Despite controversies surrounding cardiovascular morbidity and treatment in the setting of prostate cancer, no studies examining these issues as primary end points were identified. The low number of eligible studies since 2010 is a limitation of this analysis.

Injection of testosterone may be safer and more effective than transdermal administration for combating loss of muscle and bone in older men

The value of testosterone replacement therapy (TRT) for older men is currently a topic of intense debate. While US testosterone prescriptions have tripled in the past decade (9), debate continues over the risks and benefits of TRT. TRT is currently prescribed for older men with either low serum testosterone (T) or low T plus accompanying symptoms of hypogonadism. The normal range for serum testosterone is 300 to 1,000 ng/dl. Serum T ≤ 300 ng/dl is considered to be low, and T ≤ 250 is considered to be frank hypogonadism. Most experts support TRT for older men with frank hypogonadism and symptoms. Treatment for men who simply have low T remains somewhat controversial. TRT is most frequently administered by intramuscular (im) injection of long-acting T esters or transdermally via patch or gel preparations and infrequently via oral administration. TRT produces a number of established benefits in hypogonadal men, including increased muscle mass and strength, decreased fat mass, increased bone mineral density, and improved sexual function, and in some cases those benefits are dose dependent. For example, doses of TRT administered by im injection are typically higher than those administered transdermally, which results in greater musculoskeletal benefits. TRT also produces known risks including development of polycythemia (Hct > 50) in 6% of those treated, decrease in HDL, breast tenderness and enlargement, prostate enlargement, increases in serum PSA, and prostate-related events and may cause suppression of the hypothalamic-pituitary-gonadal axis. Importantly, TRT does not increase the risk of prostate cancer. Putative risks include edema and worsening of sleep apnea. Several recent reports have also indicated that TRT may produce cardiovascular (CV) risks, while others report no risk or even benefit. To address the potential CV risks of TRT, we have recently reported via meta-analysis that oral TRT increases CV risk and suggested that the CV risk profile for im TRT may be better than that for oral or transdermal TRT.

Outcomes of androgen replacement therapy in adult male hypogonadism: recommendations from the Italian society of endocrinology

OBJECTIVE

We developed clinical practice guidelines to assess the individual risk-benefit profile of androgen replacement therapy in adult male hypogonadism (HG), defined by the presence of specific signs and symptoms and serum testosterone (T) below 12 nmol/L.

PARTICIPANTS

The task force consisted of eight clinicians experienced in treating HG, selected by the Italian Society of Endocrinology (SIE). The authors received no corporate funding or remuneration.

CONSENSUS PROCESS

Consensus was guided by a systematic review of controlled trials conducted on men with a mean T < 12 nmol/L and by interactive discussions. The guidelines were reviewed and sequentially approved by the SIE Guidelines Commission and Executive Committee.

CONCLUSIONS

We recommend T supplementation (TS) for adult men with severely reduced T levels (T < 8 nmol/L) to improve body composition and sexual function. We suggest that TS be offered to subjects with T < 12 nmol/L to improve glycaemic control, lipid profile, sexual function, bone mineral density, muscle mass and depressive symptoms, once major contraindications have been ruled out. We suggest that lifestyle changes and other available interventions (e.g. for erectile dysfunction) be suggested prior to TS. We suggest that TS should be combined with currently available treatments for individuals at high risk for complications, such as those with osteoporosis and/or metabolic disorders. We recommend against using TS to improve cardiac outcome and limited mobility. We recommend against using TS in men with prostate cancer, unstable cardiovascular conditions or elevated haematocrit. The task force places a high value on the timely treatment of younger and middle-aged subjects to prevent the long-term consequences of hypoandrogenism.

Cardiovascular risks and elevation of serum DHT vary by route of testosterone administration: a systematic review and meta-analysis

BACKGROUND

Potential cardiovascular (CV) risks of testosterone replacement therapy (TRT) are currently a topic of intense interest. However, no studies have addressed CV risk as a function of the route of administration of TRT.

METHODS

Two meta-analyses were conducted, one of CV adverse events (AEs) in 35 randomized controlled trials (RCTs) of TRT lasting 12 weeks or more, and one of 32 studies reporting the effect of TRT on serum testosterone and dihydrotestosterone (DHT).

RESULTS

CV risks of TRT: Of 2,313 studies identified, 35 were eligible and included 3,703 mostly older men who experienced 218 CV-related AEs. No significant risk for CV AEs was present when all TRT administration routes were grouped (relative risk (RR) = 1.28, 95% confidence interval (CI): 0.76 to 2.13, P = 0.34). When analyzed separately, oral TRT produced significant CV risk (RR = 2.20, 95% CI: 1.45 to 3.55, P = 0.015), while neither intramuscular (RR = 0.66, 95% CI: 0.28 to 1.56, P = 0.32) nor transdermal (gel or patch) TRT (RR = 1.27, 95% CI: 0.62 to 2.62, P = 0.48) significantly altered CV risk. Serum testosterone/DHT following TRT: Of 419 studies identified, 32 were eligible which included 1,152 men receiving TRT. No significant difference in the elevation of serum testosterone was present between intramuscular or transdermal TRT. However, transdermal TRT elevated serum DHT (5.46-fold, 95% CI: 4.51 to 6.60) to a greater magnitude than intramuscular TRT (2.20-fold, 95% CI: 1.74 to 2.77).

CONCLUSIONS

Oral TRT produces significant CV risk. While no significant effects on CV risk were observed with either injected or transdermal TRT, the point estimates suggest that further research is needed to establish whether administration by these routes is protective or detrimental, respectively. Differences in the degree to which serum DHT is elevated may underlie the varying CV risk by TRT administration route, as elevated serum dihydrotestosterone has been shown to be associated with CV risk in observational studies.

Adverse effects of testosterone replacement therapy: an update on the evidence and controversy

Testosterone replacement therapy (TRT) has been used in millions of men worldwide to treat diminished libido and erectile dysfunction, and to improve strength and physical function. The estimated likelihood of adverse effects of long-term TRT is still essentially unknown, as overall high-quality evidence based upon prospective randomized trials to recommend for or against its use in most men with testosterone deficiency (TD) is lacking. Evidence to suggest that TRT increases cardiovascular morbidity and mortality risks is poor, as results vary across study populations and their baseline comorbidities. While TRT may increase serum prostate-specific antigen levels in some men, it often remains within clinically acceptable ranges, and has not been shown to increase the risk of prostate cancer. Current literature supports that TRT does not substantially worsen lower urinary tract symptoms, and may actually improve symptoms in some men. Limited evidence suggests that TRT may initially worsen obstructive sleep apnea in some men, but that this is not a longstanding effect. TRT may result in erythrocytosis in some men, however long-term studies have not reported significant adverse events (e.g. cerebrovascular accident, vascular occlusive events, venous thromboembolisms). Future research will require dedicated focus on evaluation of large, multiethnic cohorts of men through prospective trials to better elucidate both risk and hazard ratios of TRT as it relates to cardiovascular disease, prostate cancer, lower urinary tract symptoms, obstructive sleep apnea, erythrocytosis, and other to-be-determined theoretical risks in men both with and without cardiovascular risk equivalents.

The Effect of Testosterone on Cardiovascular Disease

Cardiovascular disease is the leading cause of death in the United States. Testosterone is the principal male sex hormone and plays an important role in men’s health and well-being. Historically, testosterone was believed to adversely affect cardiovascular function. However, contemporary literature has refuted this traditional thinking; testosterone has been suggested to have a protective effect on cardiovascular function through its effects on the vascular system. Data from modern research indicate that hypogonadism is closely related to the development of various cardiovascular risk factors, including hyperlipidemia and insulin resistance. Several studies have demonstrated beneficial effects of testosterone supplementation therapy on reversing symptoms of hypogonadism and improving cardiovascular disease risk profiles. In this review, we perform a critical analysis on the association between testosterone and cardiovascular disease.