====== Searching ClinicalTrials.gov ======

This doc describes how to use Boolean search to retrieve records from ClinicalTrials.gov.

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<WRAP center round info 60%> To perform a ClinicalTrials.gov search into your nest, you can either 1. Write a query from scratch, or 2. Copy and paste the query from a search in ClinicalTrials.gov. Guidance for both options is given below. </WRAP>

===== How to write a ClinicalTrials.gov query =====

Use AND/OR/NOT, in combination with keywords to narrow in on trials of interest. [[https://clinicaltrials.gov/ct2/results?cond=&term=dizziness+AND+NOT+exhaustion+AND+stroke&cntry=&state=&city=&dist=|For example]]:

''dizziness AND NOT exhaustion AND stroke''

will retrieve trials with the word "dizziness" and "stroke" contained //somewhere// in the record: the trial title, description, interventions, conditions, or several other fields; trials with "exhaustion" mentioned anywhere will be excluded from results. Use parentheses if the logical operators become numerous and ambiguous, and use quotes if your keywords contain spaces.

To generate a more precise search than the Basic Search outlined above, use AREA to search specific fields. If you wanted to [[https://clinicaltrials.gov/search?term=AREA[ConditionSearch]dizziness AND NOT AREA[ConditionSearch]exhaustion AND AREA[ConditionSearch]stroke|limit your search]] to only trials with these keywords as Conditions being studied:

''AREA[ConditionSearch]dizziness AND NOT AREA[ConditionSearch]exhaustion AND AREA[ConditionSearch]stroke''

The syntax for AREA searches is simply AREA[//area name//]//search//. Common area names include:

   * **BasicSearch:**  This is the default, when no AREA is specified. It searches all of the common fields within trials
  * **ConditionSearch:**  Searches indexed conditions, condition MeSH terms, the title, and keywords
  * **InterventionSearch:**  Searches indexed interventions, intervention MeSH terms, arm labels, keywords, and more
  * **OutcomeSearch:**  Searches all outcome fields registered (Primary, Secondary, and Other)
  * **TitleSearch:**  Searches the trial name & acronym
In action, [[https://clinicaltrials.gov/ct2/results?cond=AREA[ConditionSearch]stroke+AND+AREA[InterventionSearch]TREVO+AND+AREA[OutcomeSearch]mortality&term=&cntry=&state=&city=&dist=|here's a search]] for trials assessing mortality of stroke patients treated with the Trevo device:

''AREA[ConditionSearch]stroke AND AREA[InterventionSearch]Trevo AND AREA[OutcomeSearch]mortality''

===== Testing your Search Before Running =====

You may wish to inspect the quality or volume of results retrieved prior to running an [[:wiki:autolit:search:execute|API Import]] on Nested Knowledge. To test your search, copy paste the search string into [[https://www.clinicaltrials.gov|https://www.clinicaltrials.gov]] in the "Other Terms" text input. Note that if you are using [[https://classic.clinicaltrials.gov/|"Classic ClinicalTrials.gov" ]](will be going offline in 2024), results will be different (+/- 1% in our experience), due to searching differences between the versions. Nested Knowledge API integration uses the newer version.

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===== AREAs =====

ClinicalTrials.gov publishes a full list of AREAs that may be searched & which fields are included in that AREA [[https://www.clinicaltrials.gov/data-api/about-api/search-areas|here]]. While BasicSearch, ConditionSearch, InterventionSearch, and OutcomeSearch are most common, field-level AREAs like DesignAllocation and OverallStatus may be useful for certain review types or protocols. [[https://clinicaltrials.gov/ct2/results?cond=&term=AREA[DesignAllocation]Randomized+AND+AREA[OverallStatus]Completed+AND+AREA[InterventionSearch]Trevo&cntry=&state=&city=&dist=|For example]], to retrieve completed randomized trials of the Trevo device:

''AREA[DesignAllocation]Randomized AND AREA[OverallStatus]Completed AND AREA[InterventionSearch]Trevo''

===== Operators =====

A full listing of operators may be found [[https://www.clinicaltrials.gov/api/gui/ref/expr|here]]. While AND/OR/NOT/()/""/AREA are expected to be most common, operators such as RANGE can prove useful. [[https://clinicaltrials.gov/ct2/results?cond=&term=AREA[ConditionSearch]COVID-19+and+AREA[StartDate]RANGE[01/01/2022,+MAX]&cntry=&state=&city=&dist=|For example]], to retrieve the most recent trials on COVID-19:

''AREA[ConditionSearch]COVID-19 and AREA[StartDate]RANGE[01/01/2022, MAX]''

===== Alternative Option: Copy Query from ClinicalTrials.gov =====

If you have already performed a search in ClinicalTrials.gov, and simply want to copy that query into Literature Search so it continues updating on your schedule, follow these steps:

  - Input search terms as normal and click "Search"

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  - In the search bars at the top click "Advanced Search"

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  - Then click "Expert Search" in the top right

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  - Your query will then be displayed in the correct format. Copy and paste this into the automatic search in NK.

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===== Integration with NK =====

You can conduct searches of clinicaltrials.gov on the [[:wiki:autolit:search:execute|Search]] module of the NK platform. Results from this search will automatically mark papers as [[:wiki:autolit:screening:relatedreports|]].