User’s Guide
CDE Components
Each CDE has a set of standard descriptive information that guides its implementation in clinical research projects:
Name: the globally unique name of the CDE.
Subject, Topic, Subtopic: the categorization of the CDE according to the project's ontology.
CDE ID: the globally unique number assigned to the CDE. CDE IDs are composed of four parts, separated by colons: Subject ID: Topic ID: Subtopic ID: unique CDE number.
Definition: the clinical definition for the CDE.
Suggested CRF Label: the suggested way to represent the CDE on a case report form (CRF).
Datatype: the standard coding for the CDE in a database. Consistent datatypes allow data to be combined and compared across studies. Datatypes in this project include:
Alphanumeric: any combination of numbers, letters, and symbols (i.e. free text)
Numeric: a number value, including integers and decimals
Select One Value: the selection of a single value from a predefined list for the CDE (permissible values)
Select Multiple Values: the selection of one or more values from a predefined list for the CDE (permissible values)
Measurement Type: the standard unit of measurement for the CDE, if applicable.
Permissible Values: the list of allowed selections for a CDE whose datatype is either Select One Value or Select Multiple Values.
References: the list of references used to create the definition of the CDE, where applicable.
Representing the CDEs on CRFs
Many CDEs are meant to be used together to form complete questions or concepts, such as a type of diagnostic study, the study date and time, and the study findings. CDEs used in this way can be represented in different ways on CRFs to meet data collection needs for an individual research study. In the example, we include the last position of the CDE ID for each data element as a superscript to allow easy lookup of CDE definitions and requirements.
Example: Laboratory Values
Consider a study that captures only complete blood count results with no other test information. On a CRF this can be represented as follows:
A more complex set of data that includes a combination of numeric results, date of specimen collection, and the permissible values for status and clinical significance can be represented as follows:
Referencing the CDEs in Research Publications
The methods and outcomes of this project have been published in the Journal of Thrombosis and Haemostasis:
Le Gal, G., Carrier, M., Castellucci, L.A., Cuker, A., Hansen, J.‐B., Klok, F.A., Langlois, N.J., Levy, J.H., Middeldorp, S., Righini, M., Walters, S. and (2020), Development and implementation of common data elements for venous thromboembolism research: Official Communication from the SSC of the ISTH. J Thromb Haemost. Accepted Author Manuscript. https://doi.org/10.1111/jth.15138
When using the ISTH CDEs in your research, please include this reference in your citations.
Frequently Asked Questions
What if my study uses different measurement types than the CDE requires?
We recognize that all organizations may not use the same measurement types (e.g. g/L, mg/dL) for results. If your organization uses a different measurement type than what is defined for a CDE, you can continue to capture these data in your local measurement type for your study purposes, and then convert to the CDE-defined measurement type when publishing findings and comparing results across studies.
What if the CDE definition includes a full date and time, but we only capture part of this (e.g. year only, or date only) for our study?
Many of the CDEs allow for capturing detailed dates and times, but not all studies require this level of detail. You will note in many CDE definitions for date and time fields that we specify that date only, or part of a date, is acceptable based on study protocol and applicability of detailed date and time information.
What if we want to represent the CDE with a different label on the CRF?
CRF label text is only a suggestion, and we encourage you to use labels that make the most sense for an individual study. When sharing and comparing data, use the unique CDE Name and CDE ID in your data and publications to ensure that the data are properly referenced to the CDEs they use.
What if a selection value is not available in the permissible values list for a CDE?
Many CDEs with permissible value lists include "Other" as a selection, to allow for capturing data that are not represented by the permissible values in the list. When using "Other," check to see if there is a corresponding CDE that allows you to code a free-text answer to describe the item as well.
The CDE ID is very long; do I have to use the full ID?
The CDE ID is a "fully qualified" ID, in that it includes the Subject ID, Topic ID, Subtopic ID, and unique data element ID. For ease of use, you can reference just the unique data element ID (the last digits in the CDE ID) without the subject, topic, and subtopic IDs.
How do I determine the definition of a permissible value for a CDE?
Individual permissible value definitions are included where our workgroups determined more clarity is necessary. You can view permissible value definitions by clicking on an individual permissible value, and the definition will be displayed if it is present. If you feel that a permissible value needs a definition where one is not included, please let us know by submitting a comment for the CDE.
What if I disagree with a CDE's definition or feel that a new CDE should be included?
Please use the Contact page to send us a message regarding individual CDEs or the project as a whole. The CDE inventory is intended to be a "living" repository, and ISTH will engage its stakeholders to update it over time to maintain accuracy and relevancy in clinical research.
What if my study focusing on a clinical topic other than venous thromboembolism?
ISTH is evaluating future clinical topics for CDE development. If you have suggestions for our next clinical topic areas, please let us know what you think our priorities for future CDEs should be.