Het gevaar van ongepubliceerde onderzoeksresultaten

Conflict of interest: none declared. Financial support: none declared.

• Unpublished and selectively published trial results may lead to distortion of the effectiveness and the profile of side effects of interventions. This jeopardizes patient safety and leads to unnecessary costs.

• Between 25 and 50% of all clinical trials remain unpublished.

• Primary outcomes, as originally defined in study protocols, often differ from those in the final publication.

• Positive trial results are almost 3 times as likely to be published as negative results.

• Commercial sponsorship is strongly associated with the publication of results that promote the interests of that sponsor, but non-publication and selective reporting is also frequent among non-commercial trials.

• Existing solutions, such as the requirement for prospective registration of trial protocols and the mandatory publication of trial results within 1 year after completion of the trial will only be successful if their compliance is more strictly monitored.