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Evidence-Based Practice: Prognosis

Critical Appraisal of Prognosis Articles

1. Are the results of the prognosis study valid?
  • Was there a well-defined and representative sample of patients at a similar point in the course of their disease?
  • Was patient follow-up adequately long and complete?
  • Were patients sufficiently homogneous in prognostic factors, if not, are adjustments for important prognostic factors made?
  • Was outcome criteria objective and unbiased?
2. What are the results?
  • Did the study have a sufficiently large sample size?
  • How large is the likelihood of the outcome event(s) over a specified period of time?
    • In clinical situations event rates usually vary over time. Is a survival graph provided showing the number of discrete events occurring over time or the chance of being free of these events over time? 
  • How precise are the estimates of likelihood?
    •  What are the confidence intervals for the event rate?
3. Are the results relevant to your patient?
  • Are the study results applicable to the patients in your practice?
    • Are the study patients similiar to your own?
  • Will the results lead directly to selecting or avoiding therapy.
  • Will the results impact how you counsel your patient?

Prognosis Critical Appraisal Worksheet


Critical Appraisal Questions come from:
Laupacis A., Wells G., et al. Users' guides to the medical literature. V. How to Use an Article About Prognosis. JAMA 1994. 272(3): 234-237.
Guyatt, G. Rennie, D. Meade, MO, Cook, DJ.  Users’ Guide to Medical Literature: A Manual for Evidence-Based Clinical Practice, 2nd Edition 2008.
Sackett, DL, et al. Evidence Based Medicine: How to Practice and Teach EBM. 2nd ed. Edinburgh: Churchill Livingstone, 2000. BHSL Call Number: WB 102 E933 2000
Tips on Critical Appraisal of Evidence: Prognosis. Centre for Evidence Based Medicine (Toronto)
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