Clinical Trials Registers

I'm sure you have seen in the first box on the Prisma Flow Diagram the word Registers. I frequently get this question. What is a register?  

A register in PRISMA refers to a database or other source that contains records of ongoing or completed studies that have not yet been published. These registers can include trial registries, conference proceedings, and grey literature sources, among others. The inclusion of register searching is recommended in systematic reviews to identify relevant studies that may not have been published yet, reducing the risk of publication bias. (Rayyan, 2022)

The primary purpose of registries has traditionally been to collect data to better understand long-term trends in specific populations. Data from registries hold great potential: they can help make clinical trials more efficient and less expensive and potentially bring new treatments to patients faster.  (CTTI, n.d.)

Registered clinical trials will typically provide basic information about the study, including the disease and intervention(s) being studied, a description of the study design, the location and contact information for the study, and possibly the results of the study once it has been completed.

Please note: Being registered on one of these websites is not an indication that the organization has evaluated or approved of the research.

• HHS.gov Listing of Clinical Trial Registries

  This US Department of Health & Human Services page provides links and information about many clinical trial registries from around the world.

• ClinicalTrials.gov

  The National Library of Medicine developed ClinicalTrials.gov to provide users with up-to-date information to help them locate federally and privately supported clinical trials for diseases and conditions. It contains more than 41,000 clinical studies sponsored by the National Institutes of Health, other federal agencies, and private industry. Users can search for clinical trials via the site's search tool.

• WHO ICTRP International Clinical Trials Registry Platform

  Maintained by the World Health Organization, this search platform allows users to search across the many Primary Registries in the WHO Registry Network.

• CENTRAL, the Cochrane Central Register of Controlled Trials
  The Cochrane Library contains the Cochrane Central Register of Controlled Trials (CRCT), a bibliographic database of definitive controlled trials. The database contains over 300,000 bibliographic references to controlled trials in health care together with references to clinical trials identified by contributors to the Cochrane Collaboration in MEDLINE and EMBASE. To view CRCT results, select the "Trials" tab along the top of the results list
   
• European Union Clinical Trials Register

  Good source of pediatric drug development trials. This register allows you to search for protocol and results information on: interventional clinical trials that are conducted in the European Union (EU) and the European Economic Area (EEA); clinical trials conducted outside the EU / EEA that are linked to European pediatric-medicine development. The EU clinical trials register has been a primary registry in the World Health Organization (WHO's) Registry Network since September 2011 and is a WHO Registry Network data provider. It is also available on the WHO International Clinical Trials Registry Platform.

• ISRCTN
  Is a registry containing the basic set of data items deemed essential to describe a clinical study at inception, following the requirements set out by the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and the International Committee of Medical Journal Editors (ICMJE) guidelines. All study records are freely accessible and searchable and have been assigned an ISRCTN ID.  On this site you can:

  • Register your clinical studies and update your records

  • Find and view clinical studies. Search by condition, intervention, funder, demographics, etc. and filter search results

  • Download data for further analysis

For those trials that do end in article publication, the following library databases allow users to search for the published results of clinical trials.  Each resource has the ability to limit to Clinical Trials as a publication or article type. NOTE: You would list these results under databases not Registers when completing the PRISMA.

• PubMed 

  Provided by the US National Library of Medicine, PubMed is a freely available database containing more than 26 million citations for biomedical information. PubMed provides several search options for finding information about clinical trials. After performing a search PubMed, use the Article Types filter on the left hand side of the screen. Click "Customize" to select from a variety of options, including Clinical Trial, Randomized Controlled Trial, and Clinical Trial, Phase I - IV.

• CINAHL Plus With Fulltext

  The Cumulative Index to Nursing and Alllied Health Literature contains information published from 1982 to present on nursing and allied health fields. Search results in CINAHL can be limited to clinical trials by choosing "Clinical Trial" from the "Publication Type" selection box in the Limit your Results section of the search interface.

• Medline with Fulltext
  Search results in Medline can be limited to clinical trials by choosing "Clinical Trial" from the "Publication Type" selection box in the Limit your Results section of the search interface.

• Cochrane Library 

  The Cochrane Library contains the Cochrane Central Register of Controlled Trials (CRCT), a bibliographic database of definitive controlled trials. The database contains over 300,000 bibliographic references to controlled trials in health care together with references to clinical trials identified by contributors to the Cochrane Collaboration in MEDLINE and EMBASE. To view CRCT results, select the "Trials" tab along the top of the results list.