In cardiovascular medicine as in all other medical disciplines, realizing the full value of clinical trial research data requires that the data be accessible to the research community and others who might be able to use them. Traditionally, the dissemination of knowledge derived from clinical research has been limited in scope: investigators who have designed and conducted clinical trials make the decisions about which statistical analyses to conduct and then publish peer-reviewed articles to disseminate their findings. Clinical trial data are considered the property of the investigators and the entities that sponsored the research, with little or no opportunity for investigators external to the original study team to access the data. This traditional model is based on dissemination via print publication, the origins of which date back to the seventeenth century.
By continued adherence to this model in the age of electronic knowledge exchange, our understanding of clinical interventions is limited by our lack of access to comprehensive data from all clinical trials in several ways. First, a select number of individuals decide which analyses to conduct, choosing some at the exclusion of others, while an analysis that might have been of great interest to another investigator – and which may have a direct bearing on clinical practice - may not be performed. Second, among these findings generated, a select number might be included in any peer-reviewed publication, leaving the research community and clinicians at a loss to know about what findings were generated and not disseminated. In fact, by comparing published articles to trial protocols, 50% of efficacy and 65% of harm outcomes per trial have been shown to be incompletely reported and biased toward the reporting of statistically-significant findings.1 Third, among all trials conducted, there may be significant publication delays, as happened with the Ezetimibe and Simvastatin in Hypercholesterolemia Enhances Atherosclerosis Regression [ENHANCE] trial,2 which was completed in April 2006 but the findings of which were not released until after substantial coverage in the news media in January 2008.3 Finally, only a limited number of trials are eventually published. By examining trials registered with an Institutional Review Board or the publicly-available trial registry ClinicalTrials.gov,4 submitted to the U.S. Food and Drug Administration as part of new drug applications, or presented as research abstracts at National Scientific meetings, it has been estimated that between 25% and 50% of completed trials remain unpublished.5–12
The cumulative effect is that patients, physicians and other health care professionals, and the research community are placed in the position of making clinical or research decisions with access to only a fraction of the relevant clinical evidence that might otherwise be available. Making clinical research data available outside individual pharmaceutical companies or clinical research groups has obvious value, in terms of validation, reproduction, and optimization of new knowledge generated from clinical research. But why are data not made more widely available to the scientific community? In this commentary, we will review some of the common concerns about data sharing, share some prominent examples of data sharing currently underway in cardiovascular clinical research, and conclude with our expectations for more open scientific and information exchange through data sharing that will increase the value of all clinical trial research.