Objectives: The goal for this project was to develop a comprehensive set of common data elements (CDEs), data definitions, case report forms and guidelines for use in unruptured intracranial aneurysm (UIA) and subarachnoid hemorrhage (SAH) clinical research, as part of a new joint effort between the National Institute of Neurological Disorders and Stroke (NINDS) and the National Library of Medicine of the US National Institutes of Health. These UIA and SAH CDEs will join several other neurological disease-specific CDEs that have already been developed and are available for use by research investigators.

Methods: A Working Group (WG) divided into eight sub-groups and a Steering Committee comprised of international UIA and SAH experts reviewed existing NINDS CDEs and instruments, created new elements when needed and provided recommendations for UIA and SAH clinical research. The recommendations were compiled, internally reviewed by the entire UIA and SAH WG and posted online for 6 weeks for external public comments. The UIA and SAH WG and the NINDS CDE team reviewed the final version before posting the SAH Version 1.0 CDE recommendations.

Results: The NINDS UIA and SAH CDEs and supporting documents are publicly available on the NINDS CDE ( https://www.commondataelements.ninds.nih.gov/#page=Default ) and NIH Repository ( https://cde.nlm.nih.gov/home ) websites. The recommendations are organized into domains including Participant Characteristics and Outcomes and Endpoints.

Conclusion: Dissemination and widespread use of CDEs can facilitate UIA and SAH clinical research and clinical trial design, data sharing, and analyses of observational retrospective and prospective data. It is vital to maintain an international and multidisciplinary collaboration to ensure that these CDEs are implemented and updated when new information becomes available.