evidence-based medicine ( ebm ) = médecine factuelle

Evidence-Based Medicine (EBM)

=Médecine Factuelle

C-EBLM

(IFCC-LM)(Cochrane, …)

Evidence-Based Nursing,

Evidence-Based Health-Care, …

Evidence-Based Policy, …

Evidence-Based Management,

Evidence-Based Sociology,

Evidence-Based History, …

Evidence-Based

Mathematics, …X

(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

DB, Barry MJ. Comparison of recommendations by urologists and radiation oncologists for treatment of clinically localized prostate cancer. 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.

Study 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

Treatment of high LDL cholesterol levels

Colorectal cancer

Screening for high-risk patients (genetics, colonoscopy)

Screening in persons at average risk (FOBT)

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

Recommended care received

85%: Influenzae vaccination >65y

45%: MI-beta-blockers

38%: Colorectal cancer/FOBT

24%: HbA1c X3/y

Conclusions

• patients received 54.9% (54.3-55.5) of recommended care

• strategies to reduce these deficits are warranted

Strategies?

EBM?

Niveaux de preuve?

I - Randomised TrialsII - Non -randomised Trials, Cohort studies

III - Case-control studies, case-reports

IV – Expert opinion

Annual biomedicalliterature:

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

Relative risk

(95% confidence interval)

0.1 0.2 0.5 1 2 5 10

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)

Overall (95% CI) 0.80 (0.74 - 0.86)

Mortality results from 33

trials of beta-blockers in

secondary prevention after

myocardial infarction.

Adapted from Freemantle et al BMJ 1999

0.8 1 20.5

“ 1997 1995 1993 “ 1992 1990 1988 “ 1987 1985 “ 1984 “ “ “ “ “ “ 1982 “ 1981 “ “ “ 1980 “ 1979 1975 “ 1974 1972 1967

Year

Relative Risk (95% Confidence Interval)

Cumulative meta-analysis of 33 trials of beta-blockers in secondary prevention after myocardial infarction

Calculated from Freemantle et al BMJ 1999

Publication biasAll studies conducted All studies published

All studies reviewed

Greyliterature

Systematic reviews

↓Levels of evidence

(EB) Guidelines

↓Levels of evidence (I-IV)

CONSENSUS JUDGMENT

↓

Strength of recommendation (A-D)

JUDGMENT /CONSENSUSI → AI → D

IV → D

II/III/IV → A

Cancer colorectal

dépistage de masse - FOBT

12 guidelinesUSA (ACS, 2006) OUI

USA (AGA, 2003) OUI

UK (BSG, 2000) NON

Canada (CAG, 2004) OUI

Canada (CTFPHC, 2001) OUI

Europe (2000) OUI

USA (ICSI, 2005) OUI

USA (NCCN, 2005) OUI

Australie (NHMRC, 2000) OUI

Nouvelle Zélande (NZGG, 2004) NON

Canada (QAG, 2003) OUI

Ecosse (SIGN, 2003) 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, Achkar E. Does fecal occult blood testing really reduce mortality? A reanalysis

of systematic review data. 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

colorectal cancer using the faecal occult blood test, Hemoccult. Cochrane Database Syst Rev 2007 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, New-Zealand):

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

CONCLUSION1) niveaux de preuve (balance

bénéfices/risques)

2) expertise professionnelle (multi-disciplinarité)

3) choix des patients

38%