Evidence-Based Medicine

Evidence-Based
Medicine (EBM)
=
Médecine
Factuelle
C-EBLM
(IFCC-LM)
(Cochrane, …)
Evidence-Based
Nursing,
Evidence-Based
Health-Care, …
Evidence-Based
Management,
Evidence-Based
Policy, …
Evidence-Based
Sociology,
Evidence-Based
History, …
EvidenceBased
Mathematics,
…
(EB)M
=
chaque décision médicale
se fonde sur:
1) niveaux de preuve (les plus
élevés)
2) expertise clinique
(professionnelle/scientifique)
3) choix des patients
Prejudice-, Belief-, Faith-,
Tradition-, Ideology-,
Authority-, Anarchy-Based
Medicine, …
Prejudice-based
Medicine
Fowler FJ Jr, McNaughton Collins M, Albertsen PC, Zietman A, Elliott
Comparison of
recommendations by urologists and
radiation oncologists for treatment of
clinically localized prostate cancer.
DB, Barry MJ.
JAMA 2000;283:3217-22.
The quality of health
care delivered to
adults in the United
States
McGlynn EA, Asch SM, Adams J, Keesey J, Hicks J,
DeCristofaro A, Kerr EA.
N Engl J Med 2003 Jun 26;
348(26):2635-45.
Design
- 439 indicators of quality of care for 30 acute and
chronic conditions, and preventive care
- Telephone survey
- Informed consent to examine their medical
records + interview
- Random sample of 6712 adults from 12
metropolitan areas
Examples of quality indicators
Hypertension
Change in treatment when blood
pressure is persistently high
Coronary
artery
disease
Beta-blockers after myocardial
infarction
Counselling on smoking cessation
Colorectal
cancer
Treatment of high LDL cholesterol
levels
Screening for high-risk patients
(genetics, colonoscopy)
Screening in persons at average risk
(FOBT)
Recommended care received
Medication
68,6 %
Immunization
65,7 %
Physical examination
62,9 %
Laboratory testing or
radiography
61,7 %
Surgery
56,9 %
History
43,4 %
Counselling or education
18,3 %
Recommended care received
85%: Influenzae vaccination >65y
45%: MI-beta-blockers
38%: Colorectal cancer/FOBT
24%: HbA1c X3/y
Conclusions
• patients received 54.9% (54.355.5) of recommended care
• strategies to reduce these
deficits are warranted
Strategies?
EBM?
Niveaux de
preuve?
I - Randomised Trials
II - Non -randomised Trials,
Cohort studies
III - Case-control studies, casereports
IV – Expert opinion
Annual
biomedical
literature:
17 000 books +
2 000 000
articles
(in Medline:
200 000 articles)
“The medical literature can
be compared to a
jungle.
It is fast growing, full of
dead wood,
sprinkled with hidden
treasure,
and infested with
spiders and snakes”
Systematic Reviews
(Revues Méthodiques)
= la pierre
angulaire de
l’EBM
Systematic Review
(Introduction/) Question(s) (focussed)
Materials et Methods (objectivity)
 Search (systematic) (EB-librarianship)
 Inclusion / Exclusion / Quality assessment
Results - Discussion (limitations)
(Conclusion/) Answer(s) - balance
benefits/harms (probabilités)
Meta-analysis
- results of primary studies
combined quantitatively
and statistically
- statistical power
Trial (Year)
Barber (1967)
Reynolds (1972)
Wilhelmsson (1974)
Ahlmark (1974)
Multicentre International (1975)
Yusuf (1979)
Andersen (1979)
Rehnqvist (1980)
Baber (1980)
Wilcox Atenolol (1980)
Wilcox Propanolol (1980)
Hjalmarson (1981)
Norwegian Multicentre (1981)
Hansteen (1982)
Julian (1982)
BHAT (1982)
Taylor (1982)
Manger Cats (1983)
Rehnqvist (1983)
Australian-Swedish (1983)
Mazur (1984)
EIS (1984)
Salathia (1985)
Roque (1987)
LIT 91987)
Kaul (1988)
Boissel (1990)
Schwartz low risk (1992)
Schwartz high risk (1992)
SSSD (1993)
Darasz (1995)
Basu (1997)
Aronow (1997)
Mortality results from 33
trials of beta-blockers in
secondary prevention after
myocardial infarction.
Adapted from Freemantle et al BMJ 1999
0.80 (0.74 - 0.86)
Overall (95% CI)
0.1
0.2
0.5
1
2
5
10
Relative risk
(95% confidence interval)
Cumulative meta-analysis of 33 trials of beta-blockers in
secondary prevention after myocardial infarction
Year
1967
1972
1974
“
1975
1979
“
1980
“
“
“
1981
“
1982
“
“
“
“
“
“
1984
“
1985
1987
“
1988
1990
1992
“
1993
1995
1997
“
0.5
0.8
2
1
Relative Risk (95% Confidence Interval)
Calculated from Freemantle et al BMJ 1999
Publication bias
All studies conducted
All studies published
Grey
literature
All studies reviewed
Systematic
reviews
↓
Levels of
evidence
(EB) Guidelines
↓
Levels of evidence (I-IV)
CONSENSUS
↓
JUDGMENT
Strength of
recommendation (A-D)
JUDGMENT /CONSENSUS
I → A
I→D
IV → D
II/III/IV → A
Cancer colorectal
dépistage de
masse - FOBT
12 guidelines
USA (ACS, 2006)
USA (AGA, 2003)
OUI
OUI
UK (BSG, 2000)
Canada (CAG, 2004)
Canada (CTFPHC, 2001)
Europe (2000)
NON
OUI
OUI
OUI
USA (ICSI, 2005)
USA (NCCN, 2005)
Australie (NHMRC, 2000)
OUI
OUI
OUI
Nouvelle Zélande (NZGG, 2004)
Canada (QAG, 2003)
Ecosse (SIGN, 2003)
NON
OUI
NON
8 revues
systématiques
dont 3 publiées en
2006-2007
Heresbach D,
Manfredi S, D'halluin PN, Bretagne JF, Branger B. Review in depth
and meta-analysis of controlled trials on colorectal cancer screening by faecal occult blood test
.
Eur J Gastroenterol Hepatol 2006; 18:427-433

Méta-analyse de 4 essais contrôlés
(336 000 pts) (France, UK, USA, Danemark)

Réduction de la mortalité par CCR
(RR= 0.79-0.94), pendant la durée du
dépistage uniquement (10 ans)
Moayyedi P,
systematic review data.
Achkar E. Does fecal occult blood testing really reduce mortality? A reanalysis of
Am J Gastroenterol 2006
; 101:380-4

Méta-analyse de 3 essais contrôlés randomisés
(245 000 pts) (UK, USA, Danemark)

Réduction de la mortalité par CCR (RR=
0.80-0.95)

Augmentation de la mortalité non liée au
CCR (RR= 1.00-1.04, p=0.015) [Hypothèse:
FOBT = vaccin anti-cancer?]
Hewitson P
, Glasziou P, Irwig L, Towler B, Watson E. Screening for colorectal cancer using the
faecal occult blood test, Hemoccult.
Cochrane Database Syst Rev
2007
Jan 24;(1):CD001216.
Revue systématique + méta-analyse de 4
essais contrôlés randomisés (UK, USA,
Danemark, Suède)

Réduction de la mortalité par CCR
(RR= 0.78-0.90)

Augmentation de la mortalité non liée
au CCR (RR= 1.00-1.03, non significatif)
Hewitson P
, Glasziou P, Irwig L, Towler B, Watson E. Screening for
Cochrane
Database Syst Rev 2007
colorectal cancer using the faecal occult blood test, Hemoccult.
Jan 24;(1):CD001216.
Effets bénéfiques du dépistage de masse:
-
Réduction modeste de la mortalité par CCR
-
une possible reduction de l’incidence du CCR
-
potentiellement, une chirurgie moins invasive
Effets délétères du dépistage de masse:
-
faux-positifs: conséquences psycho-sociales
-
complications des colonoscopies, des faux négatifs
-
possibilité de sur diagnostic (investigations ou traitements
inutiles et leurs complications)
9 YES:
JUDGMENT: benefits
outweighs harms
VALID judgment,
provided both benefits and
harms are mentioned in
guidelines
3 NO (UK, Scotland, NewZealand):
JUDGMENT: benefits may or may not
outweigh harms, but the structure of
health-system does not allow to
recommend for mass-screening
VALID judgment too
CONCLUSION
1) niveaux de preuve (balance
bénéfices/risques)
2) expertise professionnelle (multidisciplinarité)
3) choix des patients
38%