The Common Data Elements (CDE) is a National Institutes of Health (NIH) interagency effort to standardize naming, definitions, and data structure for clinical research variables. The goals of the overall CDE project are: (1) to disseminate standards for the collection of data from participants enrolled in studies of neurological diseases; (2) to create accessible data-collection tools for investigators that are ready to use “off-the-shelf”; (3) to encourage focused and simplified data collection to reduce the burden on investigators and practice-based clinicians to increase clinical research participation; (4) to improve study quality and reduce costs of data entry, cleaning, and analysis, by providing uniform data descriptions and tools across National Institute of Neurological Disorders and Stroke (NINDS)-funded clinical studies of treatment for neurological diseases (National Institute of Neurological Disorders and Stroke; http://www.commondataelements.ninds.nih.gov/default.aspx
The TBI Working Group (WG) sought to address these issues by prioritizing and standardizing data collection elements for adult TBI patients to facilitate comparison of research findings across studies and encourage high-quality meta-analyses of individual patient data (Maas et al., 2010, 2011
). The WG recognized that the types of data elements and assignment of priority in children (<18 years old) differ from adults. The causes and mechanisms of injury, risk factors in the medical history, contribution of birth injury, and impact of socioeconomic factors on the child's development following TBI are important pediatric considerations. In contrast to adult TBI, there are limited data on age-dependent values for physiological variables used to guide therapy for children with severe TBI, including intracranial pressure (ICP) and cerebral perfusion pressure (CPP) (Chambers et al., 2005
; Adelson et al., 2005
Overcoming such limitations will require structured data collection that accommodates pediatric physiology and brain development. Thus, the goal of this pediatric “Demographics and Clinical Assessment” WG was to develop recommendations on coding and terminology of demographics and clinical assessments for studies across the spectrum of pediatric TBI as part of the larger multi-agency effort (Whyte et al., 2010
) described by Thurmond and associates (2010
). The primary objectives were to identify data elements specific to pediatric TBI, to prioritize these elements following the criteria established for adult TBI, to present the data elements in a clear format, and to use a structure consistent with that established for TBI by the original WG (Maas et al., 2010). Following this method, various elements and modules can be used as plug-in elements and used multiple times in clinical data collections. For example, the module on “Glasgow Coma Scale (GCS) and pupils” may be recorded only on admission, or also pre-hospital, as well as daily during the acute care phase.
This group followed the approach and structure of the precedent established by the original Demographics and Clinical Assessment WG for the broad spectrum of TBI, including adult, military, and pediatric cases (Maas et al., 2010, 2011
; Menon et al., 2010
). This publication reports the generation of pediatric-specific CDE for TBI. This is the first step in an iterative process of defining CDEs that harmonize the definitions of key variables and the collection of data in clinical studies of TBI. Other pediatric-specific WGs developed data elements with recommendations for imaging, biomarkers, and outcomes assessment.
Process for selecting common data elements
Two members of the pediatric WG (P.D.A. and M.S.W.) participated in the development of CDEs for TBI that focused on adult injury, but included limited recommendations for pediatric CDEs (Maas et al., 2010, referred to as the original WG in this article). A larger pediatric WG was then formed and the progress and recommendations of the WG were discussed during teleconferences in 2009–2010. In-depth discussions were conducted during face-to-face meetings in September 2009 and March 2010. The final recommendations of the WG were incorporated into a beta version of the pediatric TBI CDEs, reviewed by all WG members, and structured to ensure compatibility with the NINDS broad CDE project.
Distinguishing core, supplemental, and emerging data elements
In accordance with the criteria used by the other CDE WGs, the elements should be applicable across the spectrum of mild to severe TBI, for acute to long-term studies, and for studies including patients early after injury and those enrolling patients at later time periods. Following the nomenclature adopted by the CDE project, CDEs were classified by priority as core, supplemental, and emerging. Core elements are intended to encompass the minimal set of measures to characterize the broad spectrum of subjects. Core data elements are data considered essential for every study, and following the consensus of the CDE Steering Committee, are limited in number. Supplemental elements provide greater depth/breadth of exploration and/or may be useful for more specialized subpopulations. Emerging elements may require further validation, but they may fill gaps in currently validated measures, and/or substitute for recommended measures once validation is complete. Supplemental and emerging elements are specific to a research hypothesis or TBI subpopulations (i.e., children with concussion or abusive head trauma). Both may include a higher number of data elements because of the need for high data granularity and high resolution. As supplemental and emerging elements are refined and validated, some may need reclassification as core data elements, as well as future grouping of core data elements for particular types of studies (i.e., acute care clinical trials).
Categorizing elements as core/supplemental/emerging as proposed by the planning committee (Thurmond et al., 2010
) is an unresolved issue for the CDE project, including pediatric TBI. The definition of a core element for an acute phase study may differ from what is considered a core element for an epidemiological or rehabilitation-oriented study. The broad range of settings and types of studies within TBI, including pediatric TBI, therefore precludes a large number of core clinical data elements that would be appropriate to all studies. Consensus did exist that as a minimum, the most relevant measures of injury severity and predictors for outcome should be collected in studies of severe and moderate TBI in the acute setting. Consistent with the consensus of the CDE Steering Committee, the number of core elements is small. Supplemental and emerging data elements can be selected appropriate to the aims of each study.
The level of detail required can vary greatly with the design and aim of a specific study. Observational studies or large pragmatic clinical trials would require less detail than highly-focused Phase II or Phase III trials. It is therefore necessary to incorporate flexibility into the supplemental recommendations so that data elements can be selected to accommodate different levels of complexity and research questions. This approach is consistent with objectives of the CDE initiative to facilitate comparisons of results or merging of data across multiple studies, in this case, pooling results from small pediatric studies or comparing pediatric to adult studies.
The product: Pediatric TBI demographics and clinical evaluation common data elements
The structure of the adult CDEs (Maas et al., 2010) was modified to accommodate the CDEs specific to pediatric TBI as summarized in . Importantly, these initial recommendations of the WG represent a beta version. The longer-term intent is to make this CDE a global initiative (Maas, 2009
). The recommendations should be field tested in studies of pediatric TBI prior to general acceptance. This field testing may also serve to provide evidence for categorizing elements as core/supplemental/emerging.
FIG. 1. Schema of sequential approach to selection of common data elements for pediatric studies (TBI, traumatic brain injury; ICP, intracranial pressure; ED, emergency department; CT, computed tomography; PTSD, post-traumatic stress disorder; HC, head circumference). (more ...)
The data elements presented here were considered to be specific to pediatric TBI. For data elements not discussed here (e.g., gender, race, and ethnicity; Bhopal et al., 1998
; Wynia et al., 2010
), the elements and their classification did not differ between the adult and pediatric set, and therefore no changes were made to those already assigned (Maas et al., 2010). In many instances there were no differences between the adult and pediatric CDEs and no changes were made to the CDEs created for the adult studies. The intent was to keep the relevance of the CDEs as broad as necessary for the different types of investigators likely to use them (i.e., epidemiological/observational studies and acute/rehabilitation clinical trials). Different formats for data collection may, however, be appropriate in different circumstances. As an example, the WG proposes different formats for coding early details of injury and referral details for patients presenting acutely versus those presenting late. For patients who present early, referral policy and time of arrival, as well as mode of transport and emergency services provision, are relevant. For patients presenting late, the main reason for presentation and more general information on delivery of initial care and the specifics of such care are more appropriate. Capturing information on the reason for presentation is important also for later characterization of the population captured. For example, mild TBI may be overreported by individuals or families with possible financial gain, but underreported by individuals highly motivated to return to team play.
A consensus on the coding of CDEs for use in pediatric TBI was achieved. The CDEs are grouped into modules which are grouped into categories. For example, the data elements “age, gender, and race” are contained in the module “demographics,” under the category “subject characteristics.” The four main categories relevant to this manuscript are: (1) Participant or Subject Characteristics (), (2) Participant History and Family History (), (3) Injury- and Disease-Related Events (), and (4) Assessments and Examinations (). A complete overview of the data elements and definitions together with the templates may be found at the NINDS website www.commondataelements.ninds.nih.gov
, and additional information is available at www.tbi-impact.org
Participant or Subject Characteristics
Participant History and Family History
Injury- and Disease-Related Events