A BMJ Open study has found that results which were posted on a now closed industry-sponsored clinical trials register – clinicalstudyresults.org – are either scattered across various other registers or no longer publicly available. Clinicalstudyresults.org was created in 2005 by the US trade group, the Pharmaceutical Research and Manufacturers Association for pharmaceutical companies to post summary results of their clinical trials.

Before clinicalstudyresults.org was shut down in 2011, the researchers downloaded the results of 244 clinical trials on six antidepressant and antipsychotic drugs. They found only 139 of the 244 trials are registered on ClinicalTrials.gov and the results are posted for only 19 of them. Some pharma companies have their own clinical trial registers where the results of some of the other trials may be available.

The researchers also looked at the first journal article published about each trial and compared it with the results posted to clinicalstudyresults.org. They found that almost half of the serious side effects – deaths, hospitalisations or significant disability – reported on clinicalstudyresults.org were not mentioned in the journal articles.

The researchers have posted the results for these trials on their own website.