Premature stopping and informed consent in AMI trials.

Clinical trials give rise to ethical dilemmas, especially in the acutely ill, but we take issue with two points raised in a recent comment on a specific acute myocardial infarction (AMI) trial. The commentators judged that the trial most likely could, and therefore should, have been terminated much earlier. By analysing the problem statistically we arrive at results that go against their intuitive judgment-they also see it as mandatory to update the patient Information sheet as trial results accrue and trends begin to emerge. In our view, interpreting subtle trends and borderline p-values must rest with data monitoring boards, not patients. Moreover, patients with AMI or in other medical emergencies need very simple instructions. Empirical studies of the consent process confirm that the idea of a genuinely informed consent is problematic in such cases.