rctapi: Query and download from ClinicalTrials.gov
Working status ✓ (18-01-2024).
Install with devtools::install_github("AdlCruz/rctapi")
Using this tool is as easy as 1, 2, 3 … 4 … 1a.
1. Build a search expression
Both "embolism" and "heart attack AND NOT stroke AND AREA[StudyType](Interventional OR Observational) AND TILT[OfficialTitle]stress"
are valid search expressions, just follow the rules.
2. Choose which fields you want
View all_fields and create your own list. E.gc("NCTId","Acronym"), or view field_lists_df for pre-made lists.for_explorer is good to start with.
3. Choose how many studies you want to return
Reliably retrieve up to 1000 studies with the max_studies argument.
4. Download study data
Putting it all together
stress_heart <- get_study_fields(search_expr = "heart attack AND NOT stroke AND AREA[StudyType](Interventional OR Observational)AND TILT[OfficialTitle]stress", fields = for_explorer, max_studies = 500)
stress_heart is a dataframe with rows of studies and columns of fields.
1a. Return an unparsed response to check your search_expression
Toggling the argument response_content = TRUE will return the entire API response.
Among the contents is the number of studies that were found to match your search expression.
Access it with stress_heart$StudyFieldsResponse$NStudiesFound
NOTE: 1a will not work unless a pre-made list is filling fields