Selection bias resulting from the requirement for prior consent in observational research: a community cohort of people with ischaemic heart disease

Abstract

This research demonstrates the potential impact of consent bias in observational research on ischaemic heart disease, a disease of everyday clinical importance in Europe. It demonstrates that clinically important prognostic variables may be associated with consent preferences. Future cohorts, dependent upon prior written consent, may contain disproportionate numbers of those who have made healthy lifestyle decisions, have previously benefited from treatment or whose clinical risk factors are already well managed. As a result, the generalisability of such research may be diminished and the effects of treatments over- or underestimated.