Transcript CMs - Natural History + our results

Guidelines in Cerebrovascular
Neurosurgery
Resident Session
December 2000
Guideline Methodology
• systematic review of the literature relating to a
disease or specific treatment condition
• categorization according to “levels of evidence”
• development of “grades of recommendation”
• generally a consensus process
Levels of evidence for rating studies of
treatment or prevention
Level
I
II
III
IV
V
VI
Description
at least one properly designed RCT
(I+: systematic overview / meta-analysis of RCTs)
RCT not meeting level I criteria (e.g. low power)
(II+ - systematic overview / meta-analysis level II)
non-randomized trial / cohort study with
contemporaneous controls
before-after study, cohort study with
noncontemporaneous controls, case-control study
case series (>10 pts) without controls
case report / case series <10 pts
Grading System for Recommendation
Grade
Definition
A
- based on one or more level I studies
B
- best evidence available is at level II
C
- best evidence available is at level III
D
- best evidence available is lower than level III
and includes expert opinion
Categories for Strength of Recommendation
Category
Definition
A
- good evidence for use
B
- moderate evidence for use
C
- poor evidence against use
D
- moderate evidence against use
E
- good evidence against use
… Still more terms …
• “Standard of care”:
– handful (Nimodipine, NASCET >70%, NASCIS)
• “Recommendations”
• “Options”
Guidelines
“Cookbook medicine”?
How to use Guidelines
• assess quality of guideline construction
• ensure applicability to your patient
• If there is high-level evidence (standard of care):
– follow it!
OR
– delineate (and document) rationale for not following it
• If the evidence is poor:
– decide based on (evidence & experience)