Rebecca Armstrong
Elizabeth Waters
Cochrane Health Promotion & Public Health Field

 Overview of systematic reviews
 Outline of The Cochrane Collaboration
 Role of the HPPH Field
 Function of systematic reviews in informing policy and practice
 Key elements of systematic reviews
 Asking answerable questions
 Searching for evidence
 Assessing quality
 Synthesising results
 Applicability and transferability

Reviews
(narrative/literature/ traditional)
Systematic reviews
Meta-analysis

 Usually written by experts in the field
 Use informal and subjective methods to collect and interpret information
 Usually narrative summaries of the evidence
Read: Klassen et al. Guides for Reading and Interpreting Systematic
Reviews. Arch Pediatr Adolesc Med 1998;152:700-704.

What is a systematic review?
A review of the evidence on a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant primary research, and to extract and analyse data from the studies that are included in the review*
*Undertaking Systematic Reviews of Research on Effectiveness. CRD’s Guidance for those Carrying Out or
Commissioning Reviews. CRD Report Number 4 (2nd Edition). NHS Centre for Reviews and Dissemination,
University of York. March 2001.

Key elements of a systematic review
Structured, systematic process involving several steps :
1. Formulate the question
2. Plan the review
3. Comprehensive search
4. Unbiased selection and abstraction process
5. Critical appraisal of data
6. Synthesis of data (may include meta-analysis)
7. Interpretation of results
All steps described explicitly in the review

Systematic vs. Narrative reviews
 Scientific approach to a review article
 Criteria determined at outset
 Comprehensive search for relevant articles
 Explicit methods of appraisal and synthesis
 Meta-analysis may be used to combine data
 Depend on authors’ inclination (bias)
 Author gets to pick any criteria
 Search any databases
 Methods not usually specified
 Vote count or narrative summary
 Can’t replicate review

 Reduce bias
 Replicability
 Resolve controversy between conflicting studies
 Identify gaps in current research
 Provide reliable basis for decision making

Limitations of systematic reviews specific to health promotion
 Results may still be inconclusive
 There may be no trials/evidence
 The trials may be of poor quality
 The intervention may be too complex to be tested by a trial
 Practice does not change just because you have the evidence of effect/effectiveness

 Interventions to promote smoke alarm ownership and function
 School-based driver education for the prevention of traffic crashes
 Helmets for preventing head and facial injuries in bicyclists
Do you think the results identified in SRs will be good, promising or absent (and potentially harmful)?

 Helmets reduce bicycle-related head and facial injuries for bicyclists of all ages involved in all types of crashes including those involving motor vehicles.
 The results provide no evidence that drive education reduces road crash involvement , and suggest that it may lead to a modest but potentially important increase in the proportion of teenagers involved in traffic crashes.
 Results from this review suggest that area-wide traffic calming in towns and cities may be a promising intervention for reducing the number of road traffic injuries and deaths. However, further rigorous evaluations of this intervention are needed.

International non-profit organisation that prepares, maintains, and disseminates systematic up-to-date reviews of health care interventions

Named in honour of Archie Cochrane, a British researcher
In 1979:
“It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials”

 Cochrane Systematic reviews : Cochrane reviews and protocols
 Database of Reviews of Effects: Other systematic reviews appraised by the Centre for Reviews and Dissemination.
 Cochrane Central Register of Controlled Trials:
Bibliography of controlled trials (some not indexed in MEDLINE).
 Health Technology Assessment Database: HTA reports
 NHS Economic evaluation database:
Economic evaluations of health care interventions.

The Cochrane Library www.thecochranelibrary.com

 Represent the needs and interests of those in health promotion and public health in Cochrane matters
 Represent Cochrane in health promotion and public health forums
 In transition from Field to Review Group
 Will edit PH reviews for the Cochrane Library

Steering Group
Centres
Review Groups
Consumer Network
Fields
Methods Groups

 Produce systematic reviews relevant to a particular disease or health issue for inclusion in the Cochrane Library
 Examples
 Airways Group
 Drug and Alcohol Group
 Heart Group
 Injuries Group
 Skin Group
 Pregnancy and Childbirth Group
 Stroke Group
 Breast Cancer Group

 Provide advice and support in the development of the methods of systematic reviews
 Examples
 Non-Randomised Studies
 Screening and Diagnostic Tests
 Empirical Methodological Studies
 Qualitative Methods

 Work to assist all Cochrane entities within a specific geographical area
 Examples
 Australasian Cochrane Centre (at Monash)
 South African Cochrane Centre
 Italian Cochrane Centre
 Chinese Cochrane Centre

 Represent an area of interest which spans a number of health problems - and hence a number of Review Groups
 Examples
 Health Promotion and Public Health Field
 Primary Health Care Field
 Cancer Network
 Child Health Field

 Cochrane Fields represent a population group, or type of care that overlaps multiple Review Group areas
 HPPH Field
 Registered in 1996
 Administered from Melbourne
 Funded by VicHealth
 Over 400 members on contact database across
>30 countries

 Elizabeth Waters (Director)
 Jodie Doyle (Coordinator)
 Rebecca Armstrong (Senior Research Fellow)
 Naomi Priest (Research Fellow)

Effectiveness:
 Does the intervention work/not work?
 Who does it work/not work for?
Other important questions:
 How does the intervention work?
 Is the intervention appropriate?
 Is the intervention feasible?
 Is the intervention and comparison relevant?

EFFECTIVENESS
A description of the populations P
An identified intervention I
An explicit comparison
Relevant outcomes
C
O

Time-consuming question:
What is the best strategy to prevent smoking in young people?

Q.
Are mass media (or school-based or community-based) interventions effective in preventing smoking in young people?

Problem, population
Young people under 25 years of age
Intervention a) Television b) Radio c) Newspapers d) Bill boards e) Posters f) Leaflets g) Booklets
Comparison Outcome a) School-based interventions b) No intervention a) objective measures of smoking (saliva thiocyanate levels, alveolar
CO) b) self-reported smoking behaviour c) Intermediate measures
(intentions, attitude, knowledge, skills) d) Media reach
Types of studies a) RCT b) Controlled before and after studies c) Time series designs

1.
Well formulated question
2.
Comprehensive data search
3.
Unbiased selection and abstraction process
4.
Critical appraisal of data
5.
Synthesis of data
6.
Interpretation of results

 Clear research question
 Comprehensive search
 All domains, no language restriction, unpublished and published literature, up-to-date
 Document the search (replicability)

1.
2.
3.
4.
5.
6.
Describe each PICO component
Start with primary concept
Find synonyms a) Identify MeSH / descriptors / subject headings b) Add textwords
Add other components of PICO question to narrow citations (may use study filter)
Examine abstracts
Use search strategy in other databases
(may need adapting)

So you want to do a ‘quick & dirty’?
 DARE
 CENTRAL
 PubMed (clinical queries, related records)
 CDC
 NICE
 Organisations who do work in your area
 …google

The Cochrane Library: www.thecochranelibrary.com

http://www.thecommunityguide.org/

National Institute for Health and
Clinical Excellence http://www.publichealth.nice.org.uk/page.aspx?o=home

Evidence for Policy and Practice Information and Coordinating Centre (EPPI-Centre) http://eppi.ioe.ac.uk

http://www.myhamilton.ca/myhamilton/CityandGo vernment/HealthandSocialServices/Research/E
PHPP/

http://www.york.ac.uk/inst/crd

 www.google.com.au
 The order of terms will effect the results so start with the obvious or key concept
 No need for ‘and’
 Google will ignore common words
 If they are important use + (e.g. policy + 3)
 Phrase searching is useful eg “suicide prevention”
 Google searches for variations on words eg diet, dietary

 Where terms have multiple meanings you can direct google to remove sites you want to avoid (e.g. bass –music)
 Keep your search strings brief
 Mental health promotion initiatives to prevent suicide in young people
 Compartmentalise your search strings
 “mental health promotion” suicide
 “Suicide prevention” “young people”
 Prevention and suicide and youth

 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
 Use the same principles for google – keep it short and sweet.
 Key features
 Journals Database
MeSH Database
Single Citation Matcher
Clinical Queries

Select the
Limits tab – just under the search string

 These next few slides show you how to search MeSH terms in PubMed. Useful if you don’t have access to electronic databases. You combine this method with the one for text words outlined above. The process for combining text words and
MeSH terms is outlines below.

Mass media interventions to prevent smoking in young people
P= Young people
STEP ONE:
Find MeSH and textwords to describe young people

Mass media interventions to prevent smoking in young people
P= Young people
MeSH: Adolescent
Child
Minors

Mass media interventions to prevent smoking in young people
P= Young people
Textwords:
Adolescent
Child
Juvenile
Young people
Student
Girl
Boy
Teenager
Young adult
Youth

Truncation $:
To pick up various forms of a word
Teen$.tw
Teenage
Teenager
Smok$.tw
Smoke
Smoking
Teenagers
Teens
Teen
Smokes
Smoker
Smokers

Wild cards ? and #:
To pick up different spellings
Colo?r.tw (? Can be substituted for one or no characters)
Colour
Color
Wom#n.tw (# Substitutes for one character)
Woman
Women

Adjacent ADJn:
 retrieves two or more query terms within n words of each other, and in any order
 Great when you are not sure of phraseology
Eg sport adj1 policy
Sport policy
Policy for sport
Eg mental adj2 health
Mental health
Mental and physical health

Mass media interventions to prevent smoking in young people
I = Mass media interventions
STEP TWO:
Find MeSH and textwords to describe mass media interventions

 MeSH
 Mass media
 Audiovisual aids
 Television
 Motion pictures
 Radio
 Telecommunications
 Newspapers
 Videotape recording
 Advertising

Mass media interventions to prevent smoking in young people
O = Prevention of smoking
STEP THREE:
Find MeSH and textwords to describe prevention of smoking

P = YOUNG PEOPLE
MeSH
……………………….
……………………….
……………………….
I = MASS MEDIA
MeSH
……………………….
……………………….
……………………….
C = (if required)
OR
OR
O = PREVENTION OF SMOKING
MeSH
……………………….
……………………….
……………………….
OR
Textwords
……………………….
……………………….
……………………….
Textwords
……………………….
……………………….
……………………….
Textwords
……………………….
……………………….
……………………….
P
AND
I
AND
C
AND
O

 Databases use different types of controlled vocabulary
 Same citations indexed differently on different databases
 Medline and EMBASE use a different indexing system for study type
 PsycINFO and ERIC do not have specific terms to identify study types
Need to develop search strategy for each database

 RCTs
 See Cochrane Reviewer’s Handbook
 Non-RCTs
 Not yet developed, research in progress
 Qualitative research
 Specific subject headings used in CINAHL, ‘qualitative research’ used in Medline
 CINAHL Filter: Edward Miner Library http://www.urmc.rochester.edu/hslt/miner/digital_library/tip_sheets/
Cinahl_eb_filters.pdf
 Systematic reviews/meta-analyses
 CINAHL: as above
 Medline http://www.urmc.rochester.edu/hslt/miner/digital_library/tip_sheets/
OVID_eb_filters.pdf
 Medline and Embase http://www.sign.ac.uk/methodology/filters.html
 PubMed

 Not all known published trials are identifiable in Medline (depending on topic)
 Only 25% of all medical journals in Medline
 Non-English language articles are underrepresented in Medline (and developing countries)
 Publication bias – tendency for investigators to submit manuscripts and of editors to accept them, based on strength and direction of results (
Olsen 2001)

 Hand searching of key journals and conference proceedings
 Scanning bibliographies/reference lists of primary studies and reviews
 Contacting individuals/agencies/ academic institutions
Neglecting certain sources may result in reviews being biased

Alison Hill, Critical Appraisal Skills Programme, Institute of Health
Sciences, Oxford http://www.evidence-based-medicine.co.uk

 Not all published and unpublished literature is of satisfactory methodological rigour
 Just because it is in a journal does not mean it is sound!
 Onus is on you to assess validity!
 Quality may be used as an explanation for differences in study results
 Guide the interpretation of findings and aid in determining the strength of inferences

1.
Selection bias
2.
Allocation bias
3.
Confounding
4.
Blinding (detection bias)
5.
Data collection methods
6.
Withdrawals and drop-outs
7.
Statistical analysis
8.
Intervention integrity

Selection bias
Intervention
Exposed to intervention
Follow-up
Outcome
Analysis
Recruit participants
Allocation
Confounding
Integrity of intervention
Intention-to-treat
Withdrawals
Blinding of outcome assessment
Data collection methods
Statistical analysis
Allocation of concealment
Control
Not exposed to intervention
Follow-up
Outcome
Analysis

 RCTs
 The Quality Assessment Tool for Quantitative
Studies
( http://www.city.hamilton.on.ca/PHCS/EPHPP/ ).
 Non-RCTs
 Cochrane Effective Practice and Organisation of Care Group ( http://www.epoc.uottawa.ca/ ).
 The Berkeley Systematic Reviews Group
(http://www.medepi.net/meta/)

Qualitative research
 … explores the subjective world. It attempts to understand why people behave the way they do and what meaning experiences have for people.
 Qualitative studies of experience
 Process evaluation
Undertaking Systematic Reviews of Research on Effectiveness. CRD’s Guidance for those Carrying
Out or Commissioning Reviews. CRD Report Number 4 (2nd Edition). NHS Centre for Reviews and
Dissemination, University of York. March 2001.

1.
Clear aims of research (goals, why it is important, relevance)
2.
Appropriate methodology (what, how, why)
3.
Sampling strategy
4.
Data collection
5.
Relationship between researcher and participants
6.
Ethical issues
7.
Data analysis
8.
Findings
9.
Value of research (context dependent)

 Quality framework
 Government Chief Social Researcher’s Office,
UK
 http://www.strategy.gov.uk/files/pdf/Quality_framewo rk.pdf
 19 question checklist for process evaluations (EPPI-Centre)

 10 questions
1.
Clearly-focused question
2.
3.
4.
5.
The right type of study included
Identifying all relevant studies
Assessment of quality of studies
Reasonable to combine studies
6.
7.
What were the results
Preciseness of results
8.
9.
Application of results to local population
Consideration of all outcomes
10.
Policy or practice change as a result of evidence
CASP

 Type III error (integrity of intervention)
 Theoretical framework of intervention
 Context
 For whom did the intervention work, why, in what circumstances, at what cost

 Studies rarely present information on differential effects of interventions
 Cannot locate studies addressing inequalities
 May need original data from authors
 Low power to detect subgroup differences

Assessing the applicability and transferability of interventions
 Applicability – whether the intervention process could be implemented in the local setting, no matter what the outcome is.
 Is it possible to run this intervention in this local setting?
 Eg. provision of condoms in area where they are not acceptable for religious reasons
Wang et al 2005

Assessing the applicability and transferability of interventions
 Transferability – if the intervention were to be implemented in the local setting, would the effectiveness of the program be similar to the level detected in the study setting?
 E.g. if the interventionists lack experience and have few skills in delivering the intervention then its effectiveness in the local setting may be lower than that demonstrated in the study setting
Wang et al 2005

Review of questions proposed by Wang et al

 Rebecca Armstrong
 rarmstrong@vichealth.vic.gov.au
 03 9667 1336
 If I can’t help you I might be able to point you in the right direction.
 If you are interested in training and support for conducting SRs or increasing uptake within your organisation, region, state please let me know