Evidence Appraisal
Evidence appraisal tests whether you can apply guidelines and trials to an individual patient. The exam expects critical reading, not memorization of conclusions.
Core rules
- Levels of evidence rank systematic reviews and randomized trials above observational studies and expert opinion, but quality within each design matters.
- Critical appraisal checks randomization, blinding, allocation concealment, follow-up and outcome definition.
- Guidelines are conditional on evidence quality and patient values; recommendations may be strong or weak.
- Applicability depends on population, setting and resource availability.
Worked example
A trial shows a new valve reduces reoperation but increases stroke. The reasoning should compare absolute risks and patient priorities, not just the primary endpoint. If the trial excluded frail patients, extrapolation to a frail candidate is limited.
Traps
Do not accept a trial abstract without checking methods; do not apply a guideline recommendation blindly when the patient was excluded from trials; do not confuse statistical significance with clinical importance; do not ignore industry funding or conflicts.