how
do you practise evidence-based medicine?
How
does one do all of this?
A
clinician practicing EBM would ideally follow a series of steps
to get to the evidence needed to make decisions on the
course(s)of treatment for his patients. As the practice
of EBM usually starts and ends with a patient.
These
steps are outlined in Table 1
Table 1: Steps in the practice of Evidence-Based Medicine
|
1.
Form answerable clinical questions |
|
2.
Search for the best external evidence |
|
3.
Critically appraise the evidence for validity and importance |
|
4.
Apply the evidence in clinical practice |
|
5.
Evaluate his performance as a practitioner of EBM |
There are eight different kinds of questions which can be asked
as is outlined in Table 2.
In
order for both the patient and the clinician to benefit, the
questions you ask a patient should be well built. Which
means that they should be directly relevant to the patient
being treated. Also try to phrase the questions in
such a way that they direct your search for information
to the relevant answers. The elements of well-constructed
clinical questions are summarized in Table 3.
Table 2: The central tasks of clinical work or where clinical
questions
may arise from.
- Clinical
findings:
How to properly gather and interpret findings from patient
history and physical examination.
|
- Etiology:
how to identify causes for disease (including its iatrogenic
forms
|
- Differential
diagnosis:
When considering the possible causes of a patient’s
clinical problem, how to rank them by likelihood,
seriousness and treatability.
|
- Diagnostic
test:
how to select and interpret diagnostic tests, in order
to confirm or exclude a diagnosis based on considering
their precision, accuracy, acceptability, expense, safety
etc
|
- Prognosis:
How to estimate the patient’s likely clinical course
over time and anticipate likely complications
of the disease.
|
- Therapy:
how to select treatment to offer patients that do more
good than harm and that are worth the efforts and costs
of using them
|
- Prevention:
how to reduce the chance of disease by identifying and
modifying risk factors and how to diagnose disease early
by screening.
|
- Self-improvement:
How to keep up to date, improve your clinical skills
and run a better, more efficient clinical practice.
|
Table 3: The four elements of well-built clinical questions
|
|
Patients
or problem |
Intervention
(a cause, a prognostic factor, a treatment, etc) |
Comparison
Intervention
(if necessary) |
Outcome(s)
|
| Tips
for Building |
Starting
with your patient, ask "How would I describe a group
of patients similar to mine?" Balance precision with
brevity |
Ask
"Which main intervention am I considering?"
Be specific |
Ask
"What is the main alternative to compare with the
intervention?" Again, be specific |
Ask
"What can I hope to accomplish?" or "What
could this exposure really affect?" Again, be specific |
| Example |
"In
patients with heart failure from dilated cardiomyopath
y who are in sinus rhythm...." |
"...
would adding anticoagulation with warfarin to standard
heart failure therapy,..." |
"when
compared with standard therapy alone,..."
|
"..lead
to lower mortality or morbidity from thromboembolis m
Is this enough to be worth the increased risk of bleeding?" |
The
best way to explain this process is to illustrate it with an
example. For this purpose we look at the following
case study:
Mr Evan Dince is a 40 year old male who has been recently diagnosed with HIV, his CD4 count is 275cells/mL. Although he is medically well, and has no complaints at present, he is anxious to start antiretroviral treatment. He asks you, his GP, for advice on the best time to start antiretroviral therapy. You decide to undertake a search of current best evidence to provide correct up-to-date information to your patient.
|
