Transcript Nessun titolo diapositiva - European Monitoring Centre for

Understanding the evidence base: the
need to critically examine all the studies
and evidence on drug related
interventions as collected and analysed
by the Cochrane Collaboration
Marina Davoli
Co-ordinating Editor Cochrane Drugs and Alcohol
Review Group
Lisbon, 6-8 May 2009
SUMMARY
• Why the evidence base
• Where is the evidence
• Future challenges and perspectives
A reminder of the responsibilities of
practitioners, policy makers and
researchers to the public
Good intentions and plausible
theories
are no substitute for
reliable evidence from empirical
research about the effects of
social and healthcare
interventions
Iain Chalmers, 8° CC 2000
Example I: SIDS
…could it be achieved
earlier?
Example 1: SIDS
Systematic review of effectiveness: RR
of death by sleep position Jilbert, IJE 2005
Example 1: SIDS
• Jilbert suggests that the delay is
attributable to a greater “believe” in
theoretical mechanisms (cardiac,
cerebral, etc) of death than in the
evidence of effectiveness
• From 1970 to 1992 10000 US and
50000 european children could have
survived if guidelines would have
issued earlier
Jilbert, IJE 2005
Example 2
Interventions
intended to prevent
delinquent
adolescents from
becoming career
criminals
The likelihood of a prison sentence for a
17-20 year old convicted of criminal
damage
•
•
•
•
•
•
•
•
•
•
Powys
Surrey
Suffolk
Norfolk
Gloucestershire
Nottinghamshire
South Yorkshire
Northumbria
Kent
Hertfordshire
5.1%
5.9%
8.1%
8.3%
9.8%
21.1%
21.9%
25.3%
26.1%
31.6%
Home Office statistics for Crown Courts in 1988, Guardian 23 Jan 90
International variation in
sentencing policy
• Sentences for a 19-year old armed robber who
stole £800,000 with four others in a bank raid
•
•
•
•
•
•
Nigeria
H Kong
Texas
Greece
England
Scotland
Death
Life
99 years
20 years
14 years
10 years
N Zealand
India
Denmark
Canada
Norway
9
7
6
5
2
years
years
years
years
years
• Survey of the International Bar Association (1990):
based on judges’ and legal experts’ responses to
hypothetical cases
RCTs of ‘Scared Straight’ programmes
Trial
Michigan 1967
Change in criminal
behaviour
26 % increase
Greater Egypt 1979
5 % increase
Yarborough 1979
1 % increase
Orchowsky 1981
2 % increase
Vreeland 1981
11 % increase
Finckenauer 1982
30 % increase
Lewis 1983
14 % increase
Petrosino et al 2000
Conclusions
Responsible professionals in the
health and social services need
more than
good intentions and plausible
theories
to guide their practice.
Their prescriptions and
proscriptions for others should be
informed by reliable research
evidence showing that they are
more likely to do good than harm.
The Cochrane Collaboration
An international network of people who
conduct, update and disseminate
systematic reviews of the effect of health
care interventions.
There are 51 Review Groups in the
Cochrane Collaboration
Cochrane Review Group on Drugs and Alcohol
The editorial base
The Editors
Marina Davoli: Co-ordinating Editor
Laura Amato: Managing Editor
Simona Vecchi:Trial search Co.
Zuzana Mitrova: Assistant Co.
Robert Ali (Australia)
Zhao Chengzheng (China)
Fabrizio Faggiano (Italy)
Michael Farrell (UK)
David Foxcroft (UK)
Walter Ling (USA)
RCTs on interventions for drug addiction (n=6530)
Specialized Register Drugs and Alcohol Cochrane Group. CL 2.2009
600
Alcohol
500
Opiates
Not specified substance
Cocaine
n° of references
400
cannabis
amphetamine
300
benzodiazepines
Other substances
200
100
0
19561975
19761980
19811985
198619911990
1995
years
19962000
20012005
2006marzo
2009
Cochrane Systematic reviews
• Are the result of a complex process :
– Formulate a proper question
– Comprehensive study search
– Objective selection and data
extraction
– Critical evaluation of primary studies
– Synthesis
– Update
State of the art CLIB 3.2009
http://www.cdag.cochrane.org
Substance
N° Reviews
N° Protocols
N° Titles
registered
Total
Alcohol
8
10
3
23
Opiate
20
4
3
27
Psychostimulants
9
2
1
12
Other
3
1
/
4
Poly drugs
4
2
6
12
Prevention
3
/
/
3
Total
47*
19
13
79
*629 studies included/1824 considered for inclusion
Effectiveness of all interventions considered in
CRs published in CLIB 3.2009
5%
26%
33%
2%
34%
beneficial or lilely to be beneficial
unknown effectiveness
likely to be ineffective or harmful
trade off between benefits and harms
unlikely to be beneficial
ALCOHOL
PSYCHOSTIMULANTS
OTHER
16,6%
27%
60%
13%
100%
N= 15
83,3
N= 8
PREVENTION
OPIATES
10%
13%
N= 25
POLY DRUGS
7%
20%
27%
43%
20%
27%
N= 48
70%
17%
N= 20
46%
Beneficial or likely to be beneficial
Trade off between benefits and harms
Likely to be ineffective or harmful
Unknown effectiveness
Unlikely to be beneficial
N= 15
http://www.who.int/substance_
abuse/publications/opioid_dep
endence_guidelines.pdf
CONCLUSIONS
• Cochrane reviews provide the “best available
evidence” answering the questions they are
planned to answer
• Cochrane reviews sometimes provide useful
results to identify effective interventions
• They also identify a wide range of interventions
unlikely to be beneficial and even likely to be
ineffective or harmful
• Cochrane reviews also help in identifying areas
where more systematic reviews are necessary
and areas where more primary research is
required
BUT….
THE EMCDDA AND THE EU SCIENTIFIC
COMMUNITY PLAY A KEY ROLE
• Ask the question:
– Help in prioritizing questions to be addressed by systematic
reviews in order to be relevant for:
• Patients and their families
• Care givers
• Policy maker
– Less than 1/3 of published studies considered for inclusion
• Support in making the evidence available and
accessible
• Use the evidence to inform guidelines
• The Cochrane Collaboration is a “virtual”
organisation open to all possible contributions
Country of origin of the studies
included in the Specialized Register
0.3%
0.5%
4.1%
4.4%
21.7%
68.3%
0.7%
Asia
Australia/New Zealand
Europe
North America
South America
South Africa
Middle East