The Double-Edged Sword of Open Access to Research Data

“In this issue of Circulation: Cardiovascular Quality and Outcomes, 2 articles have made a compelling case for an aggressive move to widespread dissemination of study data that can support other scientists' independent analyses and publications. The first article, by Gøtzsche,1 is a revised transcript of a speech made to the European Parliament in Brussels, and the second is a thoughtful commentary by Ross and colleagues.2 Both of these articles make a compelling argument that open access to clinical study data would accelerate science, illuminate new opportunities to improve care, optimally leverage existing resources to generate the most knowledge in the most cost-effective manner, and are an ethical responsibility to the patients who participated in the original studies so that their experiences can help the greatest number of individuals. These are all important points, and I wholeheartedly embrace the vision of these scholars; however, a number of practical issues need to be considered for such an approach to become a reality. First, there needs to be a means of ensuring that data are appropriately analyzed so that the results of any published findings are, in fact, true. Although the primary analysis of a randomized trial is straightforward, investigators often use these data to examine other treatments and outcomes within a longitudinal study. Although there are methods for comparing treatments or patient characteristics that are not randomly distributed in the study, such as propensity or instrumental variable techniques, a recent review of the application of these methods in cardiovascular studies revealed that