Technology has exploded and
provided us access to more information than ever before,
requiring us to scrutinize the information that we find and assess whether or
not our sources have provided us with good versus poor quality information.
Secondary sources such as the Cochran Library,
The Database of Abstracts of Reviews of Effectiveness, Clinical Evidence online,
and ACP Journal Club, can help guide us in the assessment of validity.
When you find evidence, you need to assess the validity,
the results, the relevance, the impact, and how well it applies to the clinical
case before using it to make a decision in a clinical context.
Instructors need to emphasize to learners that randomized control trials and
systematic reviews are not always a good quality.
With a randomized control trial,
you have to ask the following questions, is the study randomized?
Was it blinded?
Were the groups treated equally?
Were the subjects analyzed in groups that they were randomized to?
Was follow-up complete?
With systematic review, special attention needs to be paid to types of articles,
the databases used, the search criteria, the completeness of the search,
the inclusion, exclusion criteria, and homogeneity.
When looking at results, certain things need to be taken into consideration.
This part can involve some math and may be confusing to learners.
It is important to explain the clinical relevance and
talk trainees through the math equations and the thought processes.
Instructors must help learners realize,
it's not just memorizing the math equations, it's using them.
Useful things to understand and know how to calculate include relative risks,
odd ratios, number needed to treat, sensitivity,
specificity, negative predictive value, positive predictive value.
Finally, relevance must be assess,
you need to ask yourself to the result supplied to my patient.
From the above step, trainees can assess the quality of evidence.
After critically appraising the evidence, you need to assess at the characteristics
of the study applied to your real life patient.
Trainees should be encouraged to determine if their patient characteristics
are close enough to those found in their evidence based medicine search.
They then misuse clinical judgement to see if they can apply the information
that was found to their patient.
Trainees at this step should be encouraged to assess the patient's baseline risk,
assess the benefit to the patient using number needed to treat,
weigh the benefit versus the harm, and taken to account patient preference.
In the end, it should be emphasize to learners that evidence does not exist
to every clinical question, and if there's clinical uncertainty,
clinical judgement must take over.
Sally Santen, M.D., Ph.D.Associate Professor - Emergency Medicine
