Finding trials on the Internet: a brief guide to selected resources
Last updated May 2008
Collections of Trials
Major bibliographic databases
The largest database of trials is the Cochrane Central Register of Controlled Trials (CENTRAL). Major bibliographic databases such as MEDLINE, EMBASE and CINAHL are also rich sources of trials. These databases are often provided by large health care organisations to their employees via the Internet or an intranet. The data they contain is usually about completed trials, although CENTRAL does have records of ongoing trials.
There are often published search filters which can be used to ease the search for trials. A list of RCT filters can be found on the InterTASC Information Specialists' Sub-Group (ISSG) Search Filter Resource.
Research registers and meta-registers
HSRProj is a database of current United States projects in health services research. It is searchable along with other databases on the National Library of Medicine (NLM) gateway. It contains descriptions of research in progress in the US funded by federal and private grants and contracts for use by policy makers, managers, clinicians and other decision-makers.
ClinicalTrials.gov is a collection of clinical studies sponsored by the US National Institutes of Health (NIH), other Federal agencies, the pharmaceutical industry, and non-profit organizations in the United States.
Use the search box to find information using a few search terms. Use Advanced Search to find studies meeting specific criteria such as disease, location, treatment, sponsor and study type.
metaRegister of Controlled Trials (mRCT) is a searchable, international database of ongoing randomised controlled trials in all areas of healthcare. It also includes records of some completed trials.
Searching is via simple form filling with Boolean operators and truncation (symbol %) available. No set combination is possible. Effective searching requires us to think of a range of synonyms to use in the search to capture the topic of interest. It is not clear when new data is added to the register from its feeder databases.
Centerwatch lists recruiting trials, mainly in the USA. Includes National Cancer Institute cancer trials. Offers simple search or more advanced search with form filling and some preset categories. Offers truncation (symbol *), Boolean operators and the NEAR operator.
BioMed Central encourages trialists to publish RCTs in their open access journals. RCTs are searchable and can also be browsed on BioMed. Protocols of trials are also listed.
CORDIS(Community Research and Development Information Service) contains information on European research and development and innovation activities.
You can search all CORDIS content or search for BIOMED 2 funded projects.
HTA database is also available on the Cochrane Library, but is most current on the CRD website. Useful as technology assessments may include trials as well as reviews.
All records are MeSH coded, but given the fact that many records have quite brief indexing it may not have been possible to index to great depth. Searchers should overcompensate by also searching for trial terms in the title of the record.
WHO International Clinical Trials Registry Platform offers an International Search Portal allowing access to a database of trial registration data sets.
Pharmaceutical company registers
GlaxoSmithKline Clinical Trial Register is an alphabetical list by generic name of GlaxoSmithKline's medicines and vaccines. Trial summaries are provided where available including results and adverse effects.
Topic-specific registers
National Cancer Institute PDQ® Cancer Clinical Trials Register contains an extensive cancer clinical trials registry.
You can search NCI's listing of recruiting clinical trials or browse/search clinical trial results.
Research results registers
ClinicalStudyResults.org allows searching by drug name, study name and other options.
Clinical Trial Results is an organization of clinical trial researchers. Their goal is to rapidly disseminate clinical trial results to health care professionals.
Conference Proceedings
Conferences are often the first place we may learn about ongoing trials, and early results.
NLM Gateway search will encompass a search of some collections of meeting abstracts. It can be searched at the same time as a range of other NLM databases. Records are MeSH indexed.
medicalconferences.com allows you to search the conferences by title, date, location and keywords. You can then link to websites of the conferences identified. Those websites may have abstracts or may offer them in future, and may also offer email alerts.
Selected named conferences may put up their meeting abstracts on the organisers' website.
Experts
Experts can be identified by searching bibliographic databases but there are also websites of experts where experts list their specialisms and current research interests.
COS Expertise, a subscription service, contains over 480,000 profiles of researchers from over 1,600 institutions worldwide.
