The quality of clinical trial reporting is again under the spotlight, after a team of reseachers in Germany found problems with the majority of recent papers on bipolar disorder.

Daniel Strech, a doctor at the Hannover Medical School, and his colleagues rated all the randomized controlled trials related to bipolar disorder published between 2000 and 2008 against the checklist endorsed by the Consolidated Standards of Reporting Trials (CONSORT) group. Of the 72 items on the checklist, 42% were reported adequately and 25% inadequately in the 105 trials they analysed, they reported in January in the Journal of Clinical Psychiatry.

Key clinical information – such as the number needed to treat and the effect size – was “generally reported inadequately”, they warn.

“One could question whether doing trials with thousands of patients was really worth it if you cannot use the data,” Strech told Reuters.

Last year journals including the Lancet and the BMJ unveiled a new version of CONSORT as an analysis of 1,000 showed that despite some improvement in reporting “the quality of reporting remains well below an acceptable level”.