Transparency rules lead to large fall in positive trial results, analysis finds

Fewer large clinical trials are reporting positive findings since the introduction of measures designed to improve transparency, shows a study that analysed results from trials funded by the US National Heart, Lung, and Blood Institute (NHLBI).

The study, published in PLoS One,1 analysed 55 large randomised controlled trials carried out from 1970 to 2012 evaluating drugs or dietary supplements for treating or preventing cardiovascular disease. Trials were included if they had direct costs of over $500 000 (£322 000; €458 000) a year and were carried out in human adults with a primary outcome …