Hepcidin Reduction during Testosterone Therapy in Men with Type 2 Diabetes: A Randomized, Double-Blinded, Placebo-Controlled Study.

High hepcidin is linked to low-grade inflammation and lower iron levels. The consequences of testosterone replacement therapy (TRT) on inflammation and the risk of cardiovascular disease (CVD) are undetermined. We investigate the effect of TRT on the inflammatory cardiovascular risk markers hepcidin-iron, fibroblast growth factor 23 (FGF23)-phosphate-klotho, and calprotectin pathways. METHODS: A randomized, placebo-controlled, double-blinded study at an academic tertiary-care medical center. Interventions were testosterone gel (TRT, n = 20) or placebo gel (n = 19) for 24 weeks. We included 39 men (50-70 years) with type 2 diabetes (T2D) on metformin monotherapy with bioavailable testosterone levels <7.3 nmol/L. Body composition was assessed with DXA- and MRI-scans; the main study outcomes were serum hepcidin-iron, FGF23, phosphate, klotho, and calprotectin. RESULTS: Hepcidin levels decreased during TRT (ß = -9.5 ng/mL, p < 0.001), lean body mass (ß = 1.9 kg, p = 0.001) increased, and total fat mass (ß = -1.3 kg, p = 0.009) decreased compared to placebo. Delta hepcidin was not associated with changes in lean body mass or fat mass. Iron and the pathways of FGF23-phosphate-klotho and calprotectin were unchanged during TRT. CONCLUSIONS: During TRT, the reduction in hepcidin was not associated with circulating iron levels, lean body mass, or fat mass; these findings suggested a direct anti-inflammatory effect of TRT and no indirect effect mediated through these factors.

Adverse cardiovascular events and mortality in men during testosterone treatment: an individual patient and aggregate data meta-analysis.

Background: Testosterone is the standard treatment for male hypogonadism, but there is uncertainty about its cardiovascular safety due to inconsistent findings. We aimed to provide the most extensive individual participant dataset (IPD) of testosterone trials available, to analyse subtypes of all cardiovascular events observed during treatment, and to investigate the effect of incorporating data from trials that did not provide IPD. Methods: We did a systematic review and meta-analysis of randomised controlled trials including IPD. We searched MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, MEDLINE Epub Ahead of Print, Embase, Science Citation Index, the Cochrane Controlled Trials Register, Cochrane Database of Systematic Reviews, and Database of Abstracts of Review of Effects for literature from 1992 onwards (date of search, Aug 27, 2018). The following inclusion criteria were applied: (1) men aged 18 years and older with a screening testosterone concentration of 12 nmol/L (350 ng/dL) or less; (2) the intervention of interest was treatment with any testosterone formulation, dose frequency, and route of administration, for a minimum duration of 3 months; (3) a comparator of placebo treatment; and (4) studies assessing the pre-specified primary or secondary outcomes of interest. Details of study design, interventions, participants, and outcome measures were extracted from published articles and anonymised IPD was requested from investigators of all identified trials. Primary outcomes were mortality, cardiovascular, and cerebrovascular events at any time during follow-up. The risk of bias was assessed using the Cochrane Risk of Bias tool. We did a one-stage meta-analysis using IPD, and a two-stage meta-analysis integrating IPD with data from studies not providing IPD. The study is registered with PROSPERO, CRD42018111005. Findings: 9871 citations were identified through database searches and after exclusion of duplicates and of irrelevant citations, 225 study reports were retrieved for full-text screening. 116 studies were subsequently excluded for not meeting the inclusion criteria in terms of study design and characteristics of intervention, and 35 primary studies (5601 participants, mean age 65 years, [SD 11]) reported in 109 peer-reviewed publications were deemed suitable for inclusion. Of these, 17 studies (49%) provided IPD (3431 participants, mean duration 9·5 months) from nine different countries while 18 did not provide IPD data. Risk of bias was judged to be low in most IPD studies (71%). Fewer deaths occurred with testosterone treatment (six [0·4%] of 1621) than placebo (12 [0·8%] of 1537) without significant differences between groups (odds ratio [OR] 0·46 [95% CI 0·17-1·24]; p=0·13). Cardiovascular risk was similar during testosterone treatment (120 [7·5%] of 1601 events) and placebo treatment (110 [7·2%] of 1519 events; OR 1·07 [95% CI 0·81-1·42]; p=0·62). Frequently occurring cardiovascular events included arrhythmia (52 of 166 vs 47 of 176), coronary heart disease (33 of 166 vs 33 of 176), heart failure (22 of 166 vs 28 of 176), and myocardial infarction (10 of 166 vs 16 of 176). Overall, patient age (interaction 0·97 [99% CI 0·92-1·03]; p=0·17), baseline testosterone (interaction 0·97 [0·82-1·15]; p=0·69), smoking status (interaction 1·68 [0·41-6·88]; p=0.35), or diabetes status (interaction 2·08 [0·89-4·82; p=0·025) were not associated with cardiovascular risk. Interpretation: We found no evidence that testosterone increased short-term to medium-term cardiovascular risks in men with hypogonadism, but there is a paucity of data evaluating its long-term safety. Long-term data are needed to fully evaluate the safety of testosterone. Funding: National Institute for Health Research Health Technology Assessment Programme.

Testosterone therapy of men with type 2 diabetes mellitus - a randomized, double-blinded, placebo-controlled study.

The prevalence of chronic diseases including obesity and type 2 diabetes mellitus (T2D) are increasing. The usage of testosterone replacement therapy (TRT) has escalated in the Western countries during the past decades especially in aging men without clear organic indication for TRT although the safety of long-term TRT has not been clarified regarding the risk of cardiovascular disease (CVD). Aging men with T2D have an increased risk of CVD and these patients are often characterized by lowered T-levels, ectopic fat depots, a deranged adipokine profile with e.g. low adiponectin levels and hyperleptinaemia. However, the causal relations are unclear, and lowered T-levels could simply be a marker of illness, i.e. T2D and obesity. The aim of this randomized, double-blind, placebo-controlled study was to contribute to the clarification of the beneficial and potential harmful effects of testosterone therapy in aging men with T2D. Our results did not support evidence to beneficial effects of testosterone therapy on insulin resistance, glycemic control, or on substrate-oxidation in aging men with T2D and we cannot recommend TRT as a novel treatment for T2D. Regarding risk of CVD, the substantially reduction in subcutaneous fat (thigh and abdomen) and HDL-cholesterol levels along with unchanged ectopic fat (visceral and hepatic) during TRT might suggest an increased CVD risk. However, TRT has an ambiguous impact on the adipokine profile with a potential harmful decrease in levels of adiponectin, whereas the decrease in leptin levels and leptin: adiponectin ratio could reflect an amelioration of the CVD risk linked to hyperleptinaemia in aging men with T2D. We found that TRT for 24 weeks in aging men with T2D and lowered bio-available T-levels improved body composition with an increase in LBM and a reduction in regional and TFM. In addition to increased lean leg mass, TRT preserved knee-extensor muscle mechanical function. Although physical function was unchanged, TRT may potentially diminish the risk of developing sarcopenia resulting in a longer independent life and shorten the length of rehabilitation periods. It is still unclear whether the positive effects of TRT on muscle mass and muscle mechanical function outweigh potential negative effects especially regarding the risk for CVD. In conclusion, testosterone replacement therapy is indicated in men with clinically symptomatic hypogonadism regardless of status for T2D.