The realities of evidence-based medicine

Abstract

The rate of change of medical knowledge is staggering; the gap between what doctors know and what we should know is widening. For the individual doctor this may lead to idiosyncratic, suboptimal practice, and for the profession as a whole to unjustifiable variations in practice. There are numerous examples of such variations, due either to failure to embrace new knowledge, or to discard the “true and tried” even when it has been shown to be useless or harmful. Cardiology has not been immune from these errors. Evidence-based medicine is an attempt to harness the best available evidence from systematic research to underpin clinical practice. It does not replace individual clinical expertise and judgement; the best evidence is needed to inform clinicians and for patient choice. Gathering that evidence is often a complex process, so that increasingly clinicians are turning to bodies such as the Cochrane Collaboration, whose raison d'être is to gather and sift the evidence concerning clinical interventions. One approach to translating evidence into practice is to develop clinical practice guidelines. While there are studies which show that guidelines can assist clinicians and change their practices for the better, their usefulness and effectiveness are not yet widely accepted. Given the complexities and uncertainties of clinical medicine, it behoves us to evaluate critically such evidence as we have, and to apply it to best effect. We should try to ensure that we do not substitute fallacy for ignorance.