Faculty of Health and Medical Sciences

Appraise the evidence

Clinical Importance

Now that you know the results are valid and well-reported, are they clinically important?

A very large clinical trial may be able to show small differences between interventions that have little clinical significance. Statistical significance does not always equate to clinical significance.

Is a treatment effect (therapy) or improvement in sensitivity/specificity (diagnosis), clinically relevant? A small therapeutic benefit or improvement in sensitivity may be important for a highly fatal disease, but may not be enough to justify a new intervention in a disease with a good prognosis.
What level of uncertainty surrounds any results? Are confidence intervals given? A confidence interval shows the range of results within which the ‘true’ result is likely to fall. If a 95% confidence interval is given, this means that if a study was repeated many times within the same population, the ‘true’ value should fall within these limits 95% of the time.
If confidence intervals are given, do they encompass values that would not be clinically relevant? A larger clinical trial should give a smaller confidence interval, and a more precise estimate of the likely treatment effect.
Do the risks of a treatment or diagnostic procedure outweigh the potential benefits? What are the toxicities and side effects of an intervention?
How do these compare with the comparator arm?
Is there potential morbidity or mortality for performing a test that outweighs the benefits of making a diagnosis?