The evidence based clinician: part 5 - applying evidence to your patient
BMJ 2003; 326 doi: https://doi.org/10.1136/sbmj.030214 (Published 01 February 2003) Cite this as: BMJ 2003;326:030214
- Christopher Ball, project director1
- 1Centre for Evidence-based Medicine, Oxford OX3 7JX
Many clinical decisions depend on doctors making predictions about the likely consequences of diseases on patients. Unfortunately, risk can be difficult to understand --people and governments often behave illogically in response to perceived risk. Extremely rare conditions like variant Creutzfeldt-Jakob disease led to uproar in the media and to the government spending billions of pounds. Yet common causes of death among young people--for example, road crashes--are relatively ignored and underfunded.
Prognostic studies rarely help because they typically use complex statistical analysis to identify the relevant risk factors and then present multiple factors using numbers that do not seem to relate closely to patients' outcomes. Worse still, as we shall see, these numbers are difficult to manipulate or customise.
Evidence can help with uncertainty
Integrating prognostic information into clinical care requires care and an understanding of your patient's ideas and concerns. Everyone likes certainty, and patients often have false expectations that doctors can divine the future. Helping your patient to understand that at best clinical prediction is rudimentary may destroy some of their faith in the medical profession and lead to increased anxiety but ultimately can improve shared decision making.
Doctors and medical students need to remember that prognostic data relate to large samples of patients, and not individuals. 60% of patients in a group may have had a stroke, but this does not mean an individual patient has a 60% chance of having one--he or she will either have one (100%) or not (0%). You should, therefore, take care …
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