Home' Australian Pharmacist : February 2013 Contents Australian Pharmacist February 2013 I © Pharmaceutical Society of Australia Ltd.
EVIDENCE-BASED MEDICINE IN ACTION
The complete process of EBM has six main
steps.2,10,12 It is best to start EBM by learning
and practicing these steps. As you become
familiar with the process you can start
taking short cuts and limiting the steps.
1. Formulating a searchable clinical
2. Searching the literature efficiently.
3. Finding the study that is best able to
answer your question.
4. Appraising the literature critically.
5. Applying the results to you clinical
practice and your patients.
6. Evaluating the outcomes of the applied
evidence in your practice and patients.
This article focusses on the first three
steps. The other steps will be discussed in
detail in future articles.
1. The clinical question
Often called the ‘PICO’ or ‘PICOT’, this is
the most important step as it sets the
stage for a successful answer. It includes
four or sometimes five parts:
• The patient: refers to the patient or
population group you want to apply
• The intervention: the therapy that
you are interested in applying to
• The comparison: is the intervention
(therapy) against which the
intervention is measured. It is
important that the comparison group
ought to be a real alternative. e.g.
using a placebo for comparison in
many studies is not considered ethical
as there is acceptable treatment for the
population being studied.
• The outcome: the end point of interest to
you or your patient. These are most often
death, disability or recovery.
• The timeframe: relates to the period over
which the intervention is being studied.
This element is often omitted from the
searching process but may be considered
when deciding if the study was carried out
for a sufficient amount of time.
It is important to note that a clinical
question can be a ‘background’ or
‘foreground’ question. Background
questions are general questions about
conditions, illnesses, syndromes and
patterns of disease, and pathophysiology.
Answers to these questions are usually
found in medical textbooks.13
Foreground questions are more often about
issues of care. They query specialised and
distinct knowledge needed for specific and
relevant clinical decision-making. These are
the questions at the heart of the practice of
EBM. Components of a well-built foreground
question include the elements of ‘PICO’.
An experienced HCP will have very few
background questions. On the other hand
the novice has many unanswered questions
that are of background in nature.10,13
2. Searching effectively10,13
Efficient searching involves choosing
appropriate sources for the clinical question.
Several resources are freely available to
search for scholarly information. However,
only a small portion of articles will be
available full-text via open access.
• Synthesised sources: are collections of
the best available evidence to support
practice. The information is often
distilled into accessible formats for HCPs.
Examples include; Cochrane library,
clinical practice guidelines, Dynamed.
• Filtered sources: whose contents have
been pre-selected or pre-appraised for
their quality. Example; Cochrane Registry
of Controlled Trials (in Cochrane Library).
• Unfiltered sources: Unfiltered sources are
large databases of articles that have not
been pre-screened for quality. The searcher
must filter out the results that do not meet
their requirements using either specific
vocabulary terms of pre-formulated
searches or terms by the database.
Examples: Medline (PubMed), Scopus,
Web of Science, Google Scholar etc.
Note: The unfiltered sources can be
filtered with specific queries. For example;
Medline – Clinical Queries available under
‘more limits’; PubMed has a feature to limit
results only to systematic reviews or meta-
Suggested research design (in order of preference)
otherwise: cohort study, case -control study, case series
Prospective, blind comparison to a reference standard
Aetiology or risk
RCT (preferred) Cohort study, case-control study, case series
Cohort study (preferred): case-control study, case series
RCT (preferred), cohort, case-control, case series
RCT or qualitative studies
Prospective, blind comparison compared to the gold
Table 1: Preferred studies to answer clinical questions14
Editorials, Expert Opinion
Case Series, Case Reports
Randomized Controlled Trials
Figure 1: Levels of evidence2
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