Evidence-Based Medicine and Medical Education
Evidence-based medicine and medical education tests formulating answerable questions, appraising evidence, applying guidelines and teaching effectively. The exam asks you to use evidence with patients, not to worship it.
Core rules
- Convert uncertainty into a PICO question: population, intervention, comparison and outcome.
- Evidence hierarchies depend on the question; a randomised trial is strong for therapy, but not always for prognosis or rare harms.
- Critical appraisal checks validity, effect size, precision and applicability.
- Guidelines are aids, not substitutes for clinical judgement; check date, population and conflicts.
- Effective teaching uses needs assessment, active learning, feedback and assessment aligned with objectives.
- Shared decision-making presents benefits and harms in absolute terms and checks the patient’s preferences.
Worked example
A patient asks whether a new drug reduces stroke. A relevant randomised trial shows a relative risk reduction of 25%, but the absolute risk falls from 4% to 3% over 5 years. The reasoning: calculate absolute risk reduction = 1%, NNT = 100 over 5 years. Discuss cost, harms and the patient’s values. A 25% relative figure sounds larger than the 1% absolute benefit.
Traps
Using relative risk alone; applying trial results to excluded groups; treating a surrogate marker as a patient-important outcome; giving feedback that is vague rather than specific and timely; and ignoring applicability to the local setting.