Evidence-Based Medicine: Definition and Foundations
Evidence-based medicine (EBM) is the conscientious, explicit and judicious use of the best current evidence in making decisions about the care of individual patients. It integrates three essential components: the best available research evidence, clinical expertise, and patient values, preferences and circumstances. EBM therefore does not mean blindly following published studies or replacing clinical judgment with guidelines. It is a structured method for applying reliable evidence to a particular patient and clinical problem.
The best evidence may differ according to the clinical question. Randomised trials are generally most useful for evaluating treatment efficacy, whereas cohort or diagnostic-accuracy studies may be more appropriate for prognosis, risk factors or diagnostic tests. Evidence must also be interpreted in relation to external validity, available resources, comorbidities, patient expectations and the expertise of the treating team.
Essential features of EBM
- Formulation of an answerable question: An unstructured clinical problem is converted into a focused question, commonly using the PICO format.
- Efficient literature search: Relevant evidence is identified using appropriate databases, search terms and filters.
- Critical appraisal: The validity, importance and applicability of the evidence are assessed.
- Clinical application: The evidence is integrated with examination findings, patient preferences…