Gray Literature in Engineering

WHAT IS A CLINICAL TRIAL?

For biomedical research, using peer-reviewed sources and grey literature (e.g. clinical trials) becomes very important in filling knowledge gaps and understanding the results of a clinical outcome. According to WHO (World Health Organization), a clinical trial is defined as “any research study that prospectively assigns human participants or groups of humans to one or more health-related interventions to evaluate the effects on health outcomes".

Use the sources below to locate clinical trials from clinical registries, databases, etc.

• National Registries

Many countries have a national registry for clinical trials. Knowing the country of origin for a specific clinical trial can make it slightly easier to locate the needed information.

A few selected databases: PubMed  |  Cochrane Library  |  Dimensions Analytics  |  Embase 

PubMed

Find indexed clinical trials in PubMed. After running a search, filter the search to limit results:

Article Type → Clinical trial
Article Type → Randomized Controlled Trial

PubMed allows for further categorization of a clinical trial with options found under “See all article type filters”. After finding an article with a clinical trial, PubMed will provide an abstract or the fulltext of the article.

Cochrane Library 

CENTRAL is a repository for clinical trials from PubMed, ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), and more. CENTRAL only provides users with bibliographic data about the clinical trial article, along with the abstract of an article written about the trial. To search for clinical trials, run a search within Cochrane Library and along the top banner of the search result screen, select “Trials.”

Dimensions Analytics

Clinical trials in Dimensions Analytics are relatively easy to find. After logging in there is a category for “Clinical Trials” across the top banner. By selecting this option, users can view all the clinical trials within Dimensions. There are also additional useful filter options which can be found on the left-hand side of the page. A few of the filter options include:

→ Clinical Trial Status 
→ Researcher
→ Collaborating Funder
→ Location - Sponsor/ Collaborator
→ Sponsor/ Collaborator
→ Condition
→ Phase
→ Registry

Once a selection is made from the search results, users can view the summary and design of the clinical trial. Often, a clinical trial will be presented with a national registry identification number, this ID is a unique identifier for each trial found in a national registry. Dimensions also provides a direct link to access additional data from the national registry. Clinical trials are not available in the free version of Dimensions.

Embase 

After running a search in Embase, look along the top banner of the search result screen, select “EBM” and then “Controlled Clinical Trials.” Note: You can also search by clinical trial number in the search field option.

PATENT DATABASES

Searching for clinical trials via a patent database can be helpful at times. Try freely available sources like Google Patents, Espacenet, or the USPTO when searching for patents. Also, see our patent research guide for more patent databases. 

MANUFACTURER'S WEBSITE

Some manufacturers (e.g. pharmaceutical companies) tend to dedicate a webpage on their site in which users can search for clinical trials. Try searching these sites as another route to finding clinical trials.