Project:

State of Clinical Trials

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Improving the Public Interface for Use of Aggregate Data in ClinicalTrials.gov

One of the initial steps to improving clinical trials is to document the current state of clinical trials in order to track changes over time. The ClinicalTrials.gov registry provides information regarding characteristics of past, current, and planned clinical studies.  While initially set up to help patients locate clinical studies it has become a source for information on clinical trials, with the registry data available for bulk download; however, researchers could not easily access and analyze these data nor characterize the clinical trial enterprise as a whole prior to CTTI’s creation of the Aggregate Analysis of ClinicalTrial.gov (AACT) database. The 2010 snapshot of the state of clinical trials showed small clinical trials applying varying methodological approaches are most prevalent. Critical medical decisions require more robust and high-quality evidence. With use of AACT, the publicly-accessible ClinicalTrials.gov dataset can be used to analyze studies and characterize the current state of clinical trials, including at the individual specialty level.

The product list contains references that detail the methodology leading to the creation of AACT example analyses using AACT and points to consider when using AACT.

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Discover Additional Deliverables Generated From This Project

Publication

Recent Clinical Trials in Osteoporosis: A Firm Foundation or Falling Short? PLoS ONE

Publication

Respiratory Tract Infection Clinical Trials, 2007-2012: A Systematic Review of ClinicalTrials.gov, Annals of the American Thoracic Society

Publication

Compliance with Results Reporting at ClinicalTrials.gov, New England Journal of Medicine

*Click here to view the the dataset used for this manuscript. (The first worksheet in this Excel file contains the description and data dictionary; the second worksheet contains the data for the 13,327 studies and all of the variables used in the analysis.)

Press Release

Clinical trial sponsors fail to report results to participants, public

Publication

Clinical Trials in Peripheral Vascular Disease: Pipeline and Trial Designs: An Evaluation of the ClinicalTrials.gov Database, Circulation

Poster Presentation

AACT-Results: The Results dataset extensions for the AACT database

Presented April 2014, American Medical Informatics Association (AMIA) Joint Summits on Translational Science

Publication

The Landscape of Clinical Trials in Nephrology: A Systematic Review of ClinicalTrials.gov, American Journal of Kidney Diseases

Publication

Using ClinicalTrials.gov to Understand the State of Clinical Research in Pulmonary, Critical Care, and Sleep Medicine, AnnalsATS

Publication

The State of Infectious Diseases Clinical Trials: A Systematic Review of ClinicalTrials.gov, PLoS ONE

Publication

An Analysis of Registered Clinical Trials in Otolaryngology from 2007 to 2010, Otolaryngology — Head and Neck Surgery

Publication

Portfolio of Clinical Research in Adult Cardiovascular Disease as Reflected in ClinicalTrials.gov, JAHA

Press Release

Cancer studies often lack necessary rigor to answer key questions

Press Release

Treatments, not prevention, dominate diabetes research

Publication

Characteristics of Oncology Clinical Trials: Insights from a Systematic Analysis of ClinicalTrials.gov, JAMA Internal Medicine

Publication

Are current clinical trials in diabetes addressing important issues in diabetes care?, Diabetologia

Poster Presentation

Clinical Trials in Nephrology: A Systematic Analysis of ClinicalTrials.gov between 2007-2010

Presented November 2012, ASN Kidney Week 2012

Poster Presentation

The State of Clinical Trials in Rheumatology: A review of the clinicaltrials.gov dataset

Presented November 2012, at ACR/ARHP Annual Meeting

Publication

Status of the Pediatric Clinical Trials Enterprise: An Analysis of the US ClinicalTrials.gov Registry, Pediatrics

Poster Presentation

Osteoporosis-Related Trials in the ClinicalTrials.gov Dataset

Presented October 2012, ASBMR Annual Meeting

*The abstract was selected for poster presentation at ASBMR. However, due to unforeseen circumstances the poster presentation did not occur.

Poster Presentation

State of Diabetes-Related Trials in the ClinicalTrials.gov Dataset

Presented October 2012, EASD Annual Meeting

Poster Presentation

The State of Infectious Diseases Clinical Trials: A Systematic Analysis of ClinicalTrials.gov

Presented October 2012, IDSA Annual Meeting

Press Release

Children Underrepresented in Drug Studies

Poster Presentation

Improving the Impact of Clinical Research: A Systematic Analysis of Kidney Cancer Trials

Presented June 2012, ASCO Annual Meeting

Poster Presentation

Geographic and Network Analysis of Oncology Trials: Portfolio Assessment of ClinicalTrials.gov

Presented June 2012, ASCO Annual Meeting

Publication

Characteristics of Clinical Trials Registered in ClinicalTrials.gov, 2007-2010, JAMA

Poster Presentation

Clinical Trials in Pulmonary, Critical Care, and Sleep Medicine (PCCSM): A Systematic Analysis

Presented May 2012, ATS Conference

Poster Presentation

The State of the Oncology Clinical Trials Portfolio: Insights from ClinicalTrials.gov

Presented May 2012, SCT Annual Meeting

Press Release

Study Shows Clinical Trials Fall Short of High-­Quality Evidence Needed To Guide Medical Decision-­making

Poster Presentation

Contemporary Clinical Research in Adult Cardiovascular Medicine: A Perspective from ClinicalTrials.gov

Presented May 2012, SCT Annual Meeting

Publication

The Database for Aggregate Analysis of ClinicalTrials.gov (AACT) and Subsequent Regrouping by Clinical Specialty, PLoS One

*The Editorial Board of the 2013 IMIA Yearbook of Medical Informatics lists this publication as one of the best papers published in 2012 in the Clinical Research Informatics subfield of Medical Informatics

Poster Presentation

Clinical Trials in Peripheral Vascular Disease: Pipeline and Trial Designs-An Evaluation of the ClinicalTrials.gov Database

Presented March 2012, ACC

Poster Presentation

Assessment of clinical trials in oncology: An evaluation of 40,969 interventional trials on ClinicalTrials.gov

Presented June 2011, ASCO Annual Meeting

Poster Presentation

Preparing the Study Dataset from ClinicalTrials.Gov for analysis using disease conditions to re-group trials by clinical specialty

Presented April 2011, ACRT/SCTS/AFMR Joint Annual Meeting

Publication

The ClinicalTrials.gov Results Database — Update and Key Issues, New England Journal of Medicine

The Editorial Board of the 2013 IMIA Yearbook of Medical Informatics listed The Database for Aggregate Analysis of ClinicalTrials.gov (AACT) and Subsequent Regrouping by Clinical Specialty as one of the best papers published in 2012 in the Clinical Research Informatics subfield of Medical Informatics. 

in detail icon In Detail

Federal law requires the registration of all non-phase 1 interventional trials of drugs, biologics, or devices that were initiated after September 27, 2007, or before that date but that were still ongoing as of December 26, 2007, have at least one U.S. research site, or are conducted under an investigational-new-drug application or an investigational-device exemption. ClinicalTrials.gov is a registry of human clinical research studies hosted by the U.S. National Institutes of Health, through its National Library of Medicine (NLM), in collaboration with the Food and Drug Administration (FDA). Studies listed in the database are conducted in all 50 US states and in 174 countries. The purpose of ClinicalTrials.gov is to provide a central resource for those seeking information on individual clinical research projects and to increase visibility of human subjects' research. While this database has been useful for patients to identify potential clinical trials in which to participate, researchers were not able to effectively access and analyze the data to learn about the characteristics and effectiveness of clinical trials as a whole. Issues related to data structure, nomenclature, and changes in data collection over time presented challenges to the aggregate analysis and interpretation of these data in general and to the analysis of trials according to clinical specialty in particular.

State of Clinical Trials: “Improving the Public Interface for Use of Aggregate Data in ClinicalTrials.gov” (2010 - Ongoing)

CTTI sought to enhance the utility of ClinicalTrials.gov as a research resource by creating a restructured version of the database that analysts could more easily use to study various aspects of US clinical trials, including the following:

  • Understanding the current state of clinical trials as a whole
  • Comparing trials within or between different medical specialties, such as oncology, pediatrics, or cardiology
  • Looking for unmet need in a particular specialty
  • Seeing what’s already been done in a specialty before designing another trial in that specialty

Improving the usability of the data found on ClinicalTrials.gov could enhance its utility as a research resource.

With CTTI’s contribution of AACT, this publicly-accessible dataset will facilitate analysis of studies and permit detailed characterization and analysis of the US clinical trials enterprise as a whole; the methodology for creating specialty datasets may facilitate other efforts to analyze studies by specialty groups.

  • Creation of AACT that include the following key design features:
    • the capacity to extend the dataset by parsing existing data
    • linking to additional data resources, such as the Medical Subject Headings (MeSH) thesaurus
    • integrated metadata
  • Developed a methodology to re-group studies from ClinicalTrials.gov by clinical specialties as designated by the Department of Health and Human Services.

Detailed methodology on the creation AACT and the re-grouping of clinical studies can be found in the 2012 PLoS ONE publication.

The efforts of this CTTI project resulted in the AACT database, which allows researchers and analysts to perform analyses on a study dataset (a group of several studies) and not just within an individual study. Data from 2010 provided CTTI with a snapshot of the state of clinical trials, which showed that the clinical trial enterprise is dominated by small clinical trials, many of which are not funded by the NIH or industry, and contains significant heterogeneity in methodological approaches that typically do not provide enough robust data to guide critical medical decisions. High-quality evidence is still needed to guide medical decisions; this analysis reinforced the need to evaluate a number of aspects of the clinical trial enterprise.

CTTI also created a method to identify and group the clinical trials by specialty, such as pediatrics, infectious diseases, etc. This helps researchers know which trials have been completed in each medical specialty, or to compare trials between specialties—for example, to compare the average number of participants in cardiovascular trials to those in oncology trials. In addition to the AACT database itself, CTTI created a detailed data dictionary that provides documentation about the source, coding, and history of variables collected in AACT; a high level data dictionary containing a summary of these variables; and guidelines to consider when planning a statistical analysis of the ClinicalTrials.gov database.

The Points to Consider document provides guidelines for investigators to consider when planning a statistical analysis of the ClinicalTrials.gov database. Examples of analyses conducted using the AACT database can be in CTTI publications detailed on our products list.

Project Team Members

Rolesort descending Name Affiliation
Project Manager Sara Calvert Clinical Trials Transformation Initiative
Team Member James Topping Duke University
Team Member Karen Chiswell Duke University
Team Member Sheri Tibbs Duke University