Background and objective: Effective health care for children must be based on thorough analyses of the best research evidence. The objective of this study was to examine registration, completeness, and publication of studies involving children.
Methods: We searched the ClinicalTrials.gov registry to identify all closed studies involving children and examined them for completeness and availability of results. We examined publication in peer-reviewed journals for 160 randomly selected National Institutes of Health (NIH)-funded studies from 2000 through 2010 and for 758 randomly selected completed studies.
Results: Of 3428 closed studies involving children identified in ClinicalTrials.gov, 2385 (70%) were completed, 28 (0.8%) suspended, 152 (4.4%) terminated, and 38 (1.1%) withdrawn. The proportion of non-completed studies (terminated and suspended) increased linearly by 186% between 2001 and 2009, from 1.9% to 8.4%. Of the 152 terminated studies, 48 did not report reasons for termination, 21 cited safety concerns, and 83 cited poor recruitment or other administrative reasons. Only 29% of completed studies were published. Publication that did occur was an average of 2 years after study completion. Completed interventional studies were published more often than observational studies. Completed industry-funded studies were published less often than studies funded by the NIH. Registered NIH-funded trials were published more often than unregistered.
Conclusions: Results are unavailable for more than half of the studies involving children, revealing a substantial publication bias. Registration and posting of results on ClinicalTrials.gov should be mandatory for all studies involving children.