This article describes a challenging data monitoring experience that occurred in a major international randomized placebo-controlled trial in patients with heart failure, in which the accumulating interim data showed an excess of deaths on the active treatment.
Medical Statistics Unit, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK. stuart.pocock@lshtm.ac.uk
