Dataset Directory: Repository Profile

Clinical trial data

ClinicalTrials.gov is a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world including all 50 states and 210 countries. As of 2020 it contained over 335,000 research studies and provides access to aggregate results for nearly 30,000 clinical studies. Results submissions include all pre-specified primary and secondary outcomes as well as serious adverse events. Some studies include links to sites where the data have been deposited.

For intervention studies the description includes information regarding the dosage, length of time received, etc. For observational studies the description includes the participant groups observed along with any treatments or exposures that are of interest to the study. 

Each clinical trial entry includes: study description, study design (study type, enrollment, start and completion dates and official title), eligibility criteria, outcome measures, contacts and locations, and information on references and links to Web sites that are relevant to the study.  More recently added studies may include protocol documents, statistical analysis plans, and informed-consent forms to further inform users about a study’s design. 

ClinicalTrials.gov assigns a unique identifier, the NCT number, to each registered study. The NCT number facilitates searches for related documents about a clinical trial (e.g., publications, data repositories, press releases, and news articles).

Clinical trial, Results summary, Metadata

National Institutes of Health (NIH),

U.S. National Library of Medicine

Clinical

Africa, Asia, Central America & Caribbean, Europe, North America, Oceania, South America

Contains clinical trial research studies from 205 countries (as of 5/2020) including:

Austria, Belgium, Bulgaria, Canada, China, Costa Rica, Croatia, Cyprus, Czech Republic, Denmark, El Salvador, England, Estonia, Finland, France, Germany, Ghana, Greece, Hungary, India, Ireland, Israel, Italy, Japan, Kenya, Korea, Latvia, Lithuania, Luxembourg, Malta, Mexico, Netherlands, Nicaragua, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, UK, United States

• Provides access to a wide variety of clinical trial results. 
• Contains both intervention and observational studies
• Includes information submitted on both published and unpublished clinical trials (which may not be documented elsewhere).
• Provides access to standardized metadata across thousands of clinical trials.
• Unique identifier (NCT number) can expedite searches for related papers and other documentation.
• Study results page includes the following (if submitted):
• Participant Flow
• Baseline Characteristics
• Outcome measures and Statistical Analyses
• Adverse Events
• Limitations and Caveats
• Administrative Information

• Only includes aggregated results  (some studies include links to where to access additional data).
• Requirements for submission of results have evolved over time.
• Not all studies are fully or properly documented, see: Characterizing Major Issues in ClinicalTrials.gov Results Submissions (https://peerreviewcongress.org/prc17-0383)

https://clinicaltrials.gov/

Allows downloading of study metadata from search results list:

https://clinicaltrials.gov/ct2/resources/download 

Search options include:

• Condition or disease
• Rare diseases
• Specific drug intervention
• Dietary supplements
• Sponsors/collaborators
• Investigator

https://clinicaltrials.gov/ct2/manage-recs/background#WhyRegister

How to submit a study:

https://clinicaltrials.gov/ct2/manage-recs

How to Register

https://clinicaltrials.gov/ct2/manage-recs/how-register 

How to Submit Results:

https://clinicaltrials.gov/ct2/manage-recs/how-report 

https://clinicaltrials.gov/ct2/help/how-find/find-study-results  

No cost to access respository

Selected publications about ClinicalTrials.gov and clinical research:

https://clinicaltrials.gov/ct2/resources/pubs