Trial characteristics are not associated with treatment effects in randomized trials of testosterone therapy in men: a meta-epidemiological study

Abstract Objective To identify potential trial characteristics associated with reported treatment effect estimates in randomized trials of testosterone therapy in adult men. Design Meta-epidemiological study. Data source MEDLINE was searched for meta-analyses of randomized trials of testosterone therapy in men published between 2008 and 2018. Data extraction Data on trial characteristics were extracted independently by two reviewers. The impact of trial characteristics on reported treatment effects was investigated using a two-step meta-meta-analytic approach. Results We identified 132 randomized trials, included in 19 meta-analyses, comprising data from 10,725 participants. None of the investigated design characteristics, including year of publication, sample size, trial registration status, centre status, regionality, funding source, and conflict of interest were statistically significantly associated with reported treatment effects of testosterone therapy in men. Although trials rated at high risk of bias overall reported treatment effects that were 21% larger compared to trials rated at low risk of bias overall, the 95% confidence interval included the null (ratio of odds ratio (ROR): 0.79, 95% confidence interval: 0.60 to 1.03). Conclusions The present study found no clear evidence that trial characteristics are associated with treatment effects in randomized trials of testosterone therapy in men. To establish stronger evidence about the treatment effects of testosterone therapy in men, future randomized trials should not only be adequately designed but also transparently reported. Study registration osf.io/x9g6m