Out of the Shadows: Registration of Unreported Trials

Reports of properly conducted randomized, controlled trials are the foundation of safe and effective health care. However, a substantial proportion of all such trials never contribute to our knowledge base because they are not submitted for publication [1, 2]. This fact has several important implications for patient care. First, underreporting of trials reduces the power of systematic reviews to detect moderate but clinically important treatment effects. As a result, patients may be denied effective forms of health care. Second, because trials that show more promising treatment effects are more likely to be submitted for publication, research syntheses based on published studies can give misleading conclusions about treatment effectiveness, thereby exposing patients to useless or even harmful therapies [3]. Finally, patients may be asked to participate in new research studies designed to address questions that have already been answered [4].

Trials go unreported for myriad reasons; the most …