OBJECTIVETo determine whether testosterone therapy improves glucose metabolism in men with type 2 diabetes (T2D) and lowered testosterone. RESEARCH DESIGN AND METHODSWe conducted a randomized, double-blind, parallel, placebo-controlled trial in 88 men with T2D, aged 35-70 years with an HbA 1c £8.5% (69 mmol/mol), and a total testosterone level, measured by immunoassay, of £12.0 nmol/L (346 ng/dL). Participants were randomly assigned to 40 weeks of intramuscular testosterone undecanoate (n = 45) or matching placebo (n = 43). All study subjects were included in the primary analysis. Seven men assigned to testosterone and six men receiving placebo did not complete the study. Main outcome measures were insulin resistance by homeostatic model assessment (HOMA-IR, primary outcome) and glycemic control by HbA 1c (secondary outcome). CONCLUSIONSTestosterone therapy does not improve glucose metabolism or visceral adiposity in obese men with moderately controlled T2D and modest reductions in circulating testosterone levels typical for men with T2D.Observational studies consistently show that 30-50% of men with type 2 diabetes (T2D) have lowered circulating testosterone levels, relative to references based on healthy young men (1-3). This association is independent of age and obesity (4,5), and low testosterone levels in men with T2D are independently associated with insulin resistance (3). However, it is not known whether low testosterone levels are a cause or a consequence of T2D or its associated clinical features. Several lines of evidence lend support to the hypothesis that testosterone treatment decreases insulin resistance. Experimental evidence, reviewed in Grossmann

BackgroundWhether testosterone treatment has benefits on body composition over and above caloric restriction in men is unknown. We hypothesised that testosterone treatment augments diet-induced loss of fat mass and prevents loss of muscle mass.MethodsWe conducted a randomised double-blind, parallel, placebo controlled trial at a tertiary referral centre. A total of 100 obese men (body mass index ≥ 30 kg/m2) with a total testosterone level of or below 12 nmol/L and a median age of 53 years (interquartile range 47–60) receiving 10 weeks of a very low energy diet (VLED) followed by 46 weeks of weight maintenance were randomly assigned at baseline to 56 weeks of 10-weekly intramuscular testosterone undecanoate (n = 49, cases) or matching placebo (n = 51, controls). The main outcome measures were the between-group difference in fat and lean mass by dual-energy X-ray absorptiometry, and visceral fat area (computed tomography).ResultsA total of 82 men completed the study. At study end, compared to controls, cases had greater reductions in fat mass, with a mean adjusted between-group difference (MAD) of –2.9 kg (–5.7 to –0.2; P = 0.04), and in visceral fat (MAD –2678 mm2; –5180 to –176; P = 0.04). Although both groups lost the same lean mass following VLED (cases –3.9 kg (–5.3 to –2.6); controls –4.8 kg (–6.2 to –3.5), P = 0.36), cases regained lean mass (3.3 kg (1.9 to 4.7), P < 0.001) during weight maintenance, in contrast to controls (0.8 kg (–0.7 to 2.3), P = 0.29) so that, at study end, cases had an attenuated reduction in lean mass compared to controls (MAD 3.4 kg (1.3 to 5.5), P = 0.002).ConclusionsWhile dieting men receiving placebo lost both fat and lean mass, the weight loss with testosterone treatment was almost exclusively due to loss of body fat.Trial registrationclinicaltrials.gov, identifier NCT01616732, registration date: June 8, 2012Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-016-0700-9) contains supplementary material, which is available to authorized users.

Long-term CT follow-up of initially successfully treated PAVMs revealed successful embolotherapy of 75% and partially or completely failed embolotherapy of 25% of PAVMs.