Since the national clinical trials registry ( ) launched in February 2000, more than 360,000 research studies in the United States and over 200 countries have registered. As the characteristics of pediatric clinical studies keep changing over time and the results-reporting mechanism is under evolving, to know about the relevant updates of data elements and the effect of policies on the quality of reporting results is significant.
In this research, 53,060 clinical studies related to children registered from January 2008 to December 2019 were downloaded from on August 1st, 2020. Different types of studies and critical categorical variables were identified, based on which, Cochran-Armitage test was performed to explore temporal trend of study characteristics and common pediatric clinical conditions in four time subsets. Further, to examine heterogeneity among subgroups (funding sources, funding sites, pediatric clinical conditions,etc), chi-squared test was applied.
A total of 36,136 clinical trials and 16,692 observational studies were identified during the study period. The pediatric clinical trials increased from 7,029 (January 2008-December 2010) to 11,738 (January 2017-December 2019). The number of missing data has declined, with the maximum extent decline from 3.7 to 0.0% (Z = - 15.90, p <  0.001). Drug trials decreased from 48.8 to 28.9% (Z = - 24.68, p <  0.001). Behavioral trials, on the other hand, increased from 12.6 to 20.4% (Z = 12.28, p <  0.001). Most pediatric clinical trials were small-scale (58.9% enrolling 1-100 participants), single-site (61.4%) and funded neither by industry nor by the NIH (59.2%). The proportion of reporting study results varied by study type (χ = 1,256.8, p <  0.001), lead sponsor (χ = 4,545.6, p <  0.001), enrollment (χ = 29.4, p <  0.001) and trial phase (χ = 218.8, p <  0.001).
Pediatric clinical studies registered in were dominated by small-scale interventional trials, containing significant heterogeneity in funding sources, funding sites, pediatric clinical conditions and study characteristics. Although the results database has evolved in the past decade, efforts to strengthen the practice of systematic reporting must be continued.