Event adjudication and data monitoring in an intensive care unit observational study of thromboprophylaxis

BACKGROUND: The objective of this report is to describe the roles, responsibilities and recommendations of a 3-member Event Adjudication Committee (EAC) and a 5-member data monitoring committee (DMC) for a prospective multicenter observational study of critically ill patients with renal insufficiency examining the bioaccumulation and bleeding risk associated with dalteparin thromboprophylaxis. METHODS: The EAC reviewed bleeding events to adjudicate whether they were major or minor and whether they were related to dalteparin (uncertain, unlikely, or likely). The DMC reviewed all bleeds deemed by the EAC as uncertain or likely due to dalteparin then recommended either to continue or suspend enrolment pending review by the steering committee, or requested more information. RESULTS: Consensus on bleeding severity was achieved for all cases. At the second planned interim analysis, the EAC recommended to the DMC and steering committee that the EAC should stop adjudicating whether bleeding was related to dalteparin since attribution was challenging in this population with numerous bleeding risk factors; moreover, no bleeding rates were available from prior studies or historical or concurrent controls. CONCLUSIONS: Adjudication of whether an outcome can be attributed to an intervention in an open-label, uncontrolled observational study gives a potentially misleading impression of research oversight without methodological face validity. In this study, the EAC recommended modification of the adjudication process, and the DMC recommended continuing enrolment to achieve the target sample size.