Abstract
A third of men with type 2 diabetes (T2DM) have hypogonadotrophic hypogonadism (HH) and associated increased risk of cardiovascular and all-cause mortality. Men with HH are at increased risk of developing incident T2DM. We conducted MEDLINE, EMBASE, and COCHRANE reviews on T2DM, HH, testosterone deficiency, cardiovascular and all-cause mortality from May 2005 to October 2017, yielding 1,714 articles, 52 clinical trials and 32 randomized controlled trials (RCT). Studies with testosterone therapy suggest significant benefits in sexual function, quality of life, glycaemic control, anaemia, bone density, fat, and lean muscle mass. Meta-analyses of RCT, rather than providing clarification, have further confused the issue by including under-powered studies of inadequate duration, multiple regimes, some discontinued, and inbuilt bias in terms of studies included or excluded from analysis.