Clinical Trials.Gov: A Topical Analyses.

ClinicalTrials.gov was established as a web-based registry for clinical trials of human participants in 2000. Mandatory registration started in 2008. Given more than a decade of registered trials, it's important to understand the "topic" areas and their evolution over time from this resource. This information may help in identifying current knowledge gaps. We use dynamic topic model (DTM) methods to discover topics and their evolution over last 17 years. Our model suggests that there are disease or organ specific trials such as 'Cardiovascular disorders', Heart & Brain conditions', or 'Breast & Prostate cancer' as well as trials registered for general health. General health trials are less likely to be FDA regulated, but both health and pain management, as well as surgical, heart, and brain trials have upward trend in recent years while advanced cancer trials have downward trended. Our model derives unique insights from metadata associated with each topic area.