Evidence based knowledge is the new
science. Our knowledge in all the scientific branches including medicine
are being rewritten according to the new techniques of evidence based on
statistical facts. It is really overwhelming how scientific facts could
apparently contradict common sense and yet be right. The most famous example
was demonstrated some 400 years ago on the top of Piza tower when Galileo
carried on his famous experiment to prove that Gravity is not affected by the
weight of the body in free fall. A huge rock weighting several kilograms will
hit the ground at exactly the same time as a small piece of marble weighting
few grams. Although this seems not reasonable, but yet, it is a
scientific fact.
Evidence based knowledge is now
doing the same break through with our medical knowledge. The new facts are
categorized according to its strength in the following levels:
Level
|
Therapy
/ Prevention, Aetiology / Harm
|
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1a
|
SR (with homogeneity) of RCTs
|
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1b
|
Individual RCT (with narrow
Confidence Interval)
|
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1c
|
All or none
|
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2a
|
SR (with homogeneity) of cohort
studies
|
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2b
|
Individual cohort study
(including low quality RCT; e.g., <80% follow-up)
|
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2c
|
"Outcomes" Research;
Ecological studies
|
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3a
|
SR (with homogeneity) of
case-control studies
|
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3b
|
Individual Case-Control Study
|
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4
|
Case-series (and poor quality
cohort and case-control studies)
|
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5
|
Expert opinion without explicit
critical appraisal, or based on physiology, bench research or "first
principles"
|
Produced by Bob Phillips, Chris Ball, Dave
Sackett, Doug Badenoch, Sharon Straus, Brian Haynes, Martin Dawes since
November 1998. Updated by Jeremy Howick March 2009.
Evidence levels 1a till 2c are usually considered strong evidence beyond
all reasonable doubt; this grade is analogous to burden of proof within a
criminal court. Evidence of grades 3a till 5 are considered conclusions reached
on the balance of probabilities; this is analogous to the decision
within a civil court. (O. Garden, S. Paterson-Brown, A companion to specialist
surgical practice, 2009)
The value of developing guidelines
The value of developing guidelines
— Consensus on Evidence-Based facts
— Teaching method for junior staff
— Minimizing human errors during patient management
— Documentation of the practice
