Impact of bleeding assessment and adjudication methodology on event rates and clinical trial outcomes: insights from the HORIZONS-AMI trial

AIMS Bleeding is a major safety outcome in cardiovascular trials. The present study assessed the impact of the adjudication process of bleeding events on three-year outcomes in the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial. METHODS AND RESULTS HORIZONS-AMI enrolled 3,602 patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. An independent CEC reviewed 445 potential bleeding events identified from three sources: 339 site-reported (SR), 35 CEC-identified, and 71 database (DB)-triggered events based on programmatic identification of a decline in haemoglobin of ≥3 g/dL or in haematocrit by ≥9%; of those, 383/445 (86.1%) met the protocol definition of major bleeding. By multivariable analysis, CEC-confirmed bleeding was an independent predictor of cardiovascular death (hazard ratio [HR] 2.84, 95% confidence interval [CI]: 1.81-4.45, p