Background: Clinical trials of antithrombotic agents for the treatment of ACS routinely assess bleeding as a safety endpoint, but variation in bleeding definitions makes comparison of the relative safety of these agents difficult.
Methods: The ABC Multidisciplinary Working Group, an informal working group comprising clinical researchers and representatives from the US Food and Drug Administration, the National Institutes of Health, and the pharmaceutical industry, sought to develop a consensus approach to measuring the incidence and severity of bleeding complications during clinical trials of acute coronary syndromes (ACS). A meeting of the ABC was convened in April 2008 in Washington, DC, with the goal of developing a consensus approach to measuring the incidence and severity of hemorrhagic complications during clinical trials of ACS. Relevant literature on bleeding was reviewed through a series of short lectures and intensive group discussion.
Results: Using existing evidence on bleeding and outcomes as well as clinical judgment, criteria for the assessment of bleeding were developed through expert consensus. This consensus statement divides bleeding-related data elements into three categories: essential, recommended, and optional.
Conclusions: The ABC Group recommendations for collection and reporting of bleeding complications provide a framework for consistency in the collection of information on hemorrhagic complications in trials of ACS. Widespread adoption of the statement recommendations will facilitate understanding of the mechanisms of adverse outcomes after bleeding and comparisons of the relative safety of antithrombotic agents, as well as the interpretation of safety results from future studies.