A systematic review on beta-blockers for high blood pressure has for the first time used data from two large clinical trials that were previously unavailable. The review from the Cochrane Collaboration analysed data from eight clinical trials that included nearly 1500 patients who had been treated with either carvedilol or labetalol. The two largest trials in the review were unpublished carvedilol trials, contributing 1000 of the patients. Without these two trials, the evidence would not have been strong enough for the authors to make confident conclusions about the effects of the drug. The unpublished data was accessed through GSK’s website.

The authors of the review praised the efforts of the Cochrane Collaboration (co-founders of AllTrials) in their work towards greater clinical trials transparency.

“The public are becoming more aware of the impact that publication bias may have on medical decision-making. This is a positive change. It is likely that the unpublished data we found on the GlaxoSmithKline (GSK) web site are the result of the efforts by many Cochrane researchers pushing the company to release all RCT data.”