Post on 21-Jan-2018
Trusted evidence.Informed decisions.Better health.
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Moving Cochrane evidence into practice: past, present & futureNicola Lindson-Hawley & Jamie Hartmann-BoyceManaging Editors
Cochrane Tobacco Addiction GroupNuffield Department of Primary Care Health SciencesUniversity of Oxford
9th June 2016UKNSCC 2016London, UK
@cochraneTAG
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What we will cover
01 What is Cochrane
02 What is the Cochrane Tobacco Addiction Group (CTAG)
03 The impact of CTAG
04 How to use and interpret Cochrane evidence
05 Where should CTAG focus their efforts in future?
06 How should we disseminate to our users?
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Cochrane Organisation named after Archie Cochrane
Chalmers, Chalmers and Enkin built on Archie’s work - summarised
all the RCT data relating to the care of pregnant women
Published as ‘Effective Care in Pregnancy and Childbirth’ (Keirse,
Grant et al. 1989)
Revolutionised perinatal care and led to the formation of the
Cochrane Collaboration in 1993
Archie believed that there wasn’t
enough evidence to justify most
clinical practice and championed the
use of randomised controlled trials
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CochraneWHAT?
Gathers and combines the best evidence from
research to determine the benefits and risks of
treatments/interventions
HOW?
By systematically reviewing the available
evidence, with strong emphasis on quality
assessment
WHY?
To help healthcare providers, patients, carers, researchers, funders,
policy makers, guideline developers improve their knowledge and
make decisions
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Cochrane Protocol => Review => Update
53 topic specific Review Groups, including TAG
Worldwide- based in over 100 countries
Not-for-profit- largely government funded
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Tobacco Addiction Group (CTAG) Founded by GPs working in the Department of Public Health at the
University of Oxford (C.Silagy, T.Lancaster, G.Fowler)
The group carried out one of the first trials of nicotine patches in
primary care
They met Iain Chalmers, who was establishing Cochrane, and
carried out a prototype review of NRT for smoking cessation
Established CTAG in 1996, making 2016 our 20th anniversary
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Tobacco Addiction Group (CTAG) Main focus on interventions for tobacco
use & prevention
Manage approx. 90 reviews & 350 authors
Based at the University of Oxford in the
Primary Care Department
Funded by the National Institute for Health Research (NIHR)
@cochraneTAG
Jamie Hartmann-Boyce
Managing Editor
Nicola Lindson-Hawley
Managing Editor
Lindsay Stead
Information Specialist Tim Lancaster
Co-ordinating Editor
Paul Aveyard
Editor, University of Oxford
Robert West
Editor, University College London
John Hughes
Editor, University of Vermont
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CTAG’s aims
To inform tobacco control policy
internationally
to inform research in tobacco control,
and help ensure new research is
focussed on important unanswered
questions
to contribute to reducing tobacco use
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Recent evidence: e-cigarettes It is important that TAG reviews move with the times
The recent publication of the first version of our e-cigarette review
was an example of this (McRobbie et al. 2014)
Highlighted the lack of high quality research in the area- only 2 RCTs
met the inclusion criteria!
Received publicity worldwide,
following press release &
news briefing at the Science
Media Centre in London, UK
Due for update this year!
cochrane training
• Sources of evidence
• How to access systematic reviews via the
Cochrane Library
• How to interpret systematic reviews (key
features)
• Quiz
In this session we’ll cover….
cochrane training
Why systematic reviews?
• efficient way to access the body of research
– saves time required for searching
– critical appraisal
– interpretation of results
• explore differences between studies
• reliable basis for decision making
– unbiased selection of relevant information
– useful for health care, policy, future research
cochrane training
Key stages of a systematic review
PROTOCOL
• clearly stated objectives
• pre-defined eligibility criteria
• explicit, reproducible methodology
• Search strategy
FULL REVIEW
• systematic search
• assessment of validity of included studies
• systematic synthesis and presentation of findings
cochrane training
What is a forest plot?
Graphical display of
treatment effects from
multiple randomized
controlled trials. When
these are combined, it’s
called a meta-analysis.
cochrane training
Risk ratios (RR) in cessation reviews
For cessation, a risk ratio greater than 1 indicates that more people are quitting
in the intervention condition. For example, the below data gives us an RR of
1.5. A risk ratio of 1 means as many people quit in the control group as in the
intervention group.
Intervention
quit
Intervention
total
Control quit Control
total
15 100 10 100
RR = events in intervention group/participants in intervention group
events in control group/participants in control group
cochrane training
• Summary of key information from review
• Most important outcomes for someone
making a decision
Summary of findings tables
cochrane training
What is GRADE based on?
Quality of evidence in GRADE is based on 5 domains
Risk of bias
Inconsistency
Indirectness
Imprecision
Publication bias
The degree to which review
authors have judged each
included study to be at risk of
bias
Unexplained differences between
the results of individual studies
(heterogeneity). This can lead to
uncertainty about the underlying
effect.
Results can be downgraded because
of indirectness if:
1. Head to head comparisons are
not available
2. The population, intervention,
comparator or outcome is
different from the question the
review is trying to address
Results are considered imprecise if:
1. The total number of events is
small (usually less than 300)
2. The confidence intervals are wide
A systematic under or overestimate of
an effect due to selective publication
of studies. This can happen when the
results of a study are not reported. If,
for example, studies that detect an
effect are more likely to be published
than those with negative results, the
meta-analysis will be biased towards
positive results.
cochrane training
• Results based on trials - element of chance
• Each point estimate displayed with a
confidence interval (CI)
• CIs represented by the ends of the lines for
individual studies and by the horizontal edges
of the diamonds for pooled estimates.
• 95% CIs provide an estimated range of values
within which the true effect is 95% certain to
lie.
Each line represents an
individual study (or
intervention versus
control comparison)
The blue square
represents the point
estimate for the effect.
The size of the square is
dependent on the size of the study.
Bullen 2010 has 969 participants;
Rose 2006 96.
In this example, studies
are divided into
subgroups based on the
type of NRT.
Diamonds show a pooled
estimate, or the combined result
from all of the studies. Here,
there are pooled estimates for
studies in each subgroup and for
studies overall. This pooled
estimate represents the result of
the meta-analysis.
The vertical line is known as the line of no effect.
• For our cessation reviews, if the point estimate
is on the right side of the line, more people
receiving the intervention quit than people in
the control group. If the point estimate is on
the left side of the line, more people quit in the
control group than in the intervention group.
• If the confidence interval crosses this central
line, the effect is not statistically significant,
meaning it is possible that the intervention and
the control do not have different effects.
Stead LF, Perera R, Bullen C, Mant D, Hartmann-Boyce J, Cahill K, Lancaster T. Nicotine replacement therapy for smoking
cessation. Cochrane Database of Systematic Reviews 2012, Issue 11
cochrane training
• Get into small groups
• You have time to discuss
• You’ll be asked to share your answers
after each question
Quiz
cochrane training
How many of these studies have a statistically significant result?
a) none
b) One
c) Two
d) Three or moreAll of the studies have confidence intervals
that cross the line of no effect (1), so their
results aren’t statistically significant.
Q1
cochrane training
In how many studies did more people quit in the control group than in the
treatment group?
a) None
b) Two
c) Four
d) Seven
In four studies, the point estimate is to
the left of the line of no effect
Q2
cochrane training
• What risk ratio would you expect to see for this result?
• a) 0.5
• b) 1.0
• c) 1.5
Q3
Intervention
quit
Intervention
total
Control quit Control total
10 100 20 100
The risk ratio is less than one, because
more people quit in the control group
than in the intervention group
cochrane training
Q4. What are the PICOs?
• ParticipantsP
• InterventionsI
• ComparatorsC
• OutcomesO
• Study typeS
• Individuals who smokeP
• CytisineI
• PlaceboC
• Continuous abstinence at longest follow-upO
• Randomized controlled trialsS
cochrane training
Why was the evidence downgraded?
(can choose more than one answer)
a) Risk of bias
b) Inconsistency
c) Indirectness
d) Imprecision
e) Publication bias
The interventions being tested varied
considerably. In addition, there was
some evidence from a funnel plot to
suggest smaller studies that did not
detect significant results had not been
published.
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Cochrane TAG’s anniversary project
AIMS
Raise awareness of the group, and what we have
achieved so far
Identify areas where further research is needed in the
areas of tobacco control & smoking cessation by
involving our stakeholders
Identify specific goals for Cochrane TAG
Funded by the NIHR School for Primary Care Research
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Cochrane TAG’s anniversary projectStage 1: Identifying uncertainties survey
Asked anyone with an interest in tobacco to share the questions they
would still like to see answered by tobacco control research
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Cochrane TAG’s anniversary projectStage 2: Ranking uncertainties survey
1. E-cigarettes
2. Addressing
inequalities
Unanswered questions (uncertainties) were separated into 15
research categories, with each category consisting of 3-21
questions.
278 from the 1st survey contacted and asked to rank the 15
research categories in order of their importance. They were then
asked to rank the questions in their top 3
175 people completed the whole survey (63% of those invited)
3. Mental health
& other
substance abuse
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17th June we are holding a 1-day
workshop with 50 of our stakeholders
Discussion of where CTAG should focus
its future efforts and ways to disseminate
our findings
The findings of the project will be written
up, with our priorities & aims for the future,
and published
We will begin to work on the priorities
before the end of the year and will
continue to do so into the future
Cochrane TAG’s anniversary projectStage 3: Prioritisation Workshop
cochrane training
• Get into small groups (3-5) – choose a scribe who will feed back from each
• First 10 minutes: identify gaps in the tobacco control evidence base (see survey results if you need a steer)
• Second 10 minutes: Discuss the best ways Cochrane can get information to you
• Final 10 minutes: Feedback and discussion
Workshop