Transcript Evidence rating - Evidence-Based Medicine

Grading Evidence in Medicine
Bill Cayley Jr MD MDiv
UW Health Augusta Family Medicine
Objectives
Participants will be able to:
1. Describe the practice of evidence-based
medicine
2. Discuss the presentation and classification of
evidence
3. Discuss grading of evidence and integration into
clinical practice
What is
“evidence-based
medicine?”
Two fundamental questions…
• What is the purpose of medicine?
• How do I decide what to do?
You have to know where you’re going before
deciding how to get there…
What is the purpose of medicine?
• Patient care
• Public health
• Research
 Improving the quality of
patients’ lives…
What is evidence-based medicine?
Evidence based medicine is the conscientious,
explicit, and judicious use of current best
evidence in making decisions about the care of
individual patients.
Sackett, et al. BMJ 1996;312:71-72
What is “EBM” NOT?
• What we have always
done
• “Cookbook medicine”
• Only a cost-cutting trick
• Only randomized trials
Evidence based medicine IS…
 Tracking down the best
external evidence with which
to answer our clinical
questions…
EBM – a short history…
• JAMA 1992
“EBM: a new approach…”
• JAMA 1993 – 2000
“Users' Guides to the
Medical Literature”
• 1990s – 3 trends
– Systematic reviews
– Search engines
– Knowledge distillation
and “push” services
Classification of evidence
How do I decide what to do?
 The answer from EBM…
“…use of current best
evidence…”
Evidence: systematic observation
Meta-Analysis
Randomized Controlled Trial
Uncontrolled Trial
Case Series
Anecdote
Evidence grading
• 1989 USPSTF
– 5 levels of evidence
• Other systems:
– CEBM
– ACC
– AAFP (SORT)
– GRADE
• Detail, vs practicality
USPSTF (as of May 2007)
Grade
Definition
A
The USPSTF recommends the service. There is high certainty
that the net benefit is substantial.
Offer or provide this service.
B
The USPSTF recommends the service. There is high certainty
that the net benefit is moderate or there is moderate certainty
that the net benefit is moderate to substantial.
Offer or provide this service.
C
The USPSTF recommends against routinely providing the
service. There may be considerations that support providing
the service in an individual patient. There is at least moderate
certainty that the net benefit is small.
Offer or provide this service
only if other considerations
support the offering or providing
the service in an individual
patient.
D
The USPSTF recommends against the service. There is
moderate or high certainty that the service has no net benefit
or that the harms outweigh the benefits.
Discourage the use of this
service.
I Statement The USPSTF concludes that the current evidence is
insufficient to assess the balance of benefits and harms of the
service. Evidence is lacking, of poor quality, or conflicting, and
the balance of benefits and harms cannot be determined.
Suggestions for Practice
GRADE (a work in progress)
• GRADE classifies recommendations as strong or weak
• Strong recommendations
– mean that most informed patients would choose the recommended
management and that clinicians can structure their interactions with
patients accordingly
• Weak recommendations
– mean that patients’ choices will vary according to their values and
preferences, and clinicians must ensure that patients’ care is in
keeping with their values and preferences
 Strength of recommendation
– determined by the balance between desirable and undesirable
consequences of alternative management strategies, quality of
evidence, variability in values and preferences, and resource use
Meta-Analysis
Randomized Controlled Trial
Uncontrolled Trial
Case Series
Anecdote
More systematic observation ► better evidence
Integrating evidence & practice
What type of outcome measures?
• Surrogate markers of disease:
– Hb A1c, cholesterol, blood pressure
• Stage or extent of disease:
– Diabetic ulcers, angiographic CAD, stroke
• Patient-oriented outcomes:
– Mobility, suffering, longevity
– Morbidity and mortality
Patient or disease oriented?
• Disease-Oriented Outcomes.
– Intermediate, histopathologic, physiologic, or surrogate
results
– Examples: blood sugar, blood pressure, flow rate, coronary
plaque thickness
– May or may not reflect improvement in patient outcomes.
• Patient-Oriented Outcomes.
– Outcomes that matter to patients and help them live
longer or better lives
– Examples: including reduced morbidity, reduced mortality,
symptom improvement, improved quality of life, or lower
cost
Which outcomes????
• Topical antibiotics for bacterial conjunctivitis may improve
early and late resolution rates, but nearly all cases ultimately
have complete remission.
• Br J Gen Pract. 55: 962-4.
• Digoxin for symptomatic heart failure provides no significant
difference in mortality but is associated with lower rates of
hospitalization and of clinical deterioration.
• J Card Fail. 10:155-64.
• Long-acting beta-2 agonists for asthma are effective in
reducing symptoms but may increase mortality or
exacerbations.
• Cochrane Database of Systematic Reviews 2008, Issue 3. Art. No.: CD006363.
SORT
When guidelines conflict…
Questions of evidence
• Were the clinical questions
different?
• Were different studies
considered?
• Were the results analyzed
differently?
• Was the quality of evidence
assessed differently?
Questions of outcomes
• Did the effect estimates for
important outcomes differ?
• Did judgments about
evidence quality differ?
• Were health consequences
weighed differently?
• Were economic
consequences considered
differently?
Systems applications
Informed decision-making
1) Physicians…
•
…must recognize the role of being the patient’s agent in
helping make informed decisions to maximize benefit at
reasonable cost
2) Medical students and residents…
•
…should be educated to approach care as the patient’s
agent in making informed decisions, rather than solely as
an autonomous decision maker
3) The evidence for and approach to developing
standards should be standardized.
In short…
 EBM is the conscientious,
explicit, and judicious use of
current best evidence in
making decisions about the
care of individual patients.
Patient-oriented evidence
preferable to
Stage of disease
preferable to
 Evidence
Systematic observation =
high-quality evidence
Surrogate markers
For more information…
About EBM
• Centre for Evidence-Based
Medicine
(http://www.cebm.net/)
• Agency for Healthcare
Research and Quality
(http://www.ahrq.gov/clinic
/epcix.htm)
Evidence sources
•
•
•
•
•
•
DynaMed
(www.dynamicmedical.com/)
Essential Evidence Plus
(www.infopoems.com/)
Cochrane Library
(www.cochrane.org/)
Database of Abstracts of Reviews
of Effectiveness
(www.crd.york.ac.uk/crdweb/)
FPIN (www.fpin.org/)
Clinical Evidence
(www.clinicalevidence.com/)