Transcript Document 7292852

Supporting syntheses of the
literature
SHINE
Quality – The Whole Picture
26th November 2004
Content
• Definition and purpose
• Types of syntheses
• The role of the information specialist
– Identifying previous reviews, scoping searches,
retrieval of primary studies
• Challenges of the role
Definition and purpose
• Definition
– reduce large quantities of primary information into ‘palatable
pieces for digestion’ by decision makers (Mulrow, 1995)
– produce reliable results on which to base decisions by using
robust processes to locate, appraise and synthesise
research evidence (Song et al., 2000)
• Purpose
– Quality improvement
Systematic reviews
• ‘…a review [that] has been prepared using some kind of
systematic approach to minimising biases and random errors,
and that the components of the approach will be documented in
the materials and methods section.’ (Chalmers & Altman, 1995)
• Organisations undertaking systematic reviews
– Cochrane Collaboration
– Campbell Collaboration
– Centre for Reviews and Dissemination
Health Technology Assessments
• ‘a multidisciplinary field of policy analysis that studies
the medical, social, ethical, and economic
implications of the development, diffusion and use of
a health technology’ (INAHTA, 2000)
• Organisations undertaking HTAs
– NHS QIS
– NICE
– INAHTA
Guidelines
• ‘Clinical guidelines are systematically developed
statements to assist practitioner and patient decisions
about appropriate health care for specific clinical
circumstances.’ (www.sign.ac.uk)
• Organisations preparing evidence-based guidelines
– SIGN
– NICE
– GIN
One topic: three syntheses
• Systematic review
– In alcohol dependence, is acamprosate or naltrexone more
effective for preventing relapse?
• HTA
– Prevention of relapse in alcohol dependence
• Guideline
– The management of harmful drinking and alcohol
dependence in primary care
The role of the information specialist
• To comprehensively identify studies to
answer the review question(s)
• Stages
– Identifying previous reviews
– Undertaking scoping searches
– Retrieving primary studies
Identifying previous reviews
• Preliminary evaluation of the evidence base
– Has this question already been answered?
– If not, can an answerable question be formulated?
– Is there a reasonable evidence base?
• CDSR, DARE, HTA database, Guidelines Finder,
National Guideline Clearing House
• Ongoing reviews
• Bibliographic databases, journals and websites
Scoping searches
• ‘Scoping searches establish the feasibility of a review
question and investigate how searching and
appraisal can be operationalised.’ (Booth & Fry-Smith,
2003)
– establish the volume and quality of the primary literature
– aid development of the review protocol
– indicate how much the review might cost
Retrieval of primary studies
• Formulating clear search questions
• Recognising the ‘best’ evidence to answer the
question(s)
• Identifying the most likely sources to search
• Searching information sources effectively
(Snowball, 2002)
Formulating clear search questions
• The product
– The ‘well-built’ clinical question (Richardson et al., 1995)
– The ‘well-formulated’ question (Counsell, 1997)
– The ‘anatomy’ of a question (Sackett et al., 1997)
• The process
– Focusing the question (Oxman et al., 1993)
– Formulating the question (Counsell, 1997)
– Formulating the problem (Cochrane Handbook)
Slide reproduced with kind permission from Andrew Booth
Formulating clear search questions
• ‘Ask a poor question and you will get a poor review. A
clear question also helps the reader rapidly assess
whether the review is relevant to his or her own
clinical practice’ (Counsell, 1997).
• Clearly framed questions ‘guide much of the review
process including strategies for locating and selecting
studies or data, for critically appraising their
relevance and validity, and for analysing variation
among their results’ (Cochrane Handbook).
Slide reproduced with kind permission from Andrew Booth
Formulating clear search questions
•
•
•
•
POPULATION/PATIENT – who?
INTERVENTION/EXPOSURE – what?
COMPARISON – compared with?
OUTCOME – with what result?
• PICO, PIOC or PECO
Slide reproduced with kind permission from Andrew Booth
Worked example 1
• Population/Patients: are persons with alcohol
dependence
• Intervention: who are treated with acamprosate
• Comparison: compared with those treated with
naltrexone
• Outcome(s): less likely to relapse (into heavy
drinking and dependence)?
Worked example 2
• Population/Patients: should pregnant women be
offered
• Intervention: first trimester ultrasound scanning
(nuchal translucency measurement)
• Comparison: or second trimester serum screening
• Outcome(s): accuracy of risk assessment for
trisomy 21 (Down’s Syndrome)?
Translating PICO into a search
strategy
POPULATION
INTERVENTION
COMPARISON
OUTCOME
Alcoholics
OR
Alcoholism
Acamprosate
OR
Campral
Naltrexone
OR
Trexan
Temperance
OR
Sobriety
And
And
And
Slide reproduced with kind permission from Andrew Booth
Is PICO effective (1)?
• Statistically significant correlation between use of
PICO-structured form and complexity of search
strategy (P = 0.002) and between clinical requests
handled by PICO-structured form and fewer items
retrieved (P = 0.028). However, librarians preferred
minimally structured forms to PICO-structured forms
in every dimension except informativeness.
(Booth et al., 2000)
Slide reproduced with kind permission from Andrew Booth
Recognising the ‘best’ evidence to
answer the question
•
•
•
•
•
•
Therapy
Diagnosis, screening
Aetiology
Prognosis, natural history
Cost-effectiveness
Qualitative
(McKibbon, 1999)
Recognising the ‘best’ evidence
to answer the question
• T: In alcohol dependence, is acamprosate or naltrexone
more effective for preventing relapse?
• D: What is the accuracy of screening for alcohol problems
in primary care?
• A: What are the environmental risk factors associated with
binge drinking in college students?
• P: What is the long-term prognosis of patients with
alcoholic cardiomyopathy following total abstinence?
• CE: Are brief interventions cost-effective for problem
drinkers?
• Q: What are adolescents' perceptions of parental
alcoholism?
Identifying the sources to search (1)
• Subject
– General, eg: MEDLINE, EMBASE
– Subject-specific, eg: AMED, CINAHL, BNI
• Type of question/type of evidence
– Therapy, eg: Cochrane Database of Systematic Reviews
(CDSR); Cochrane Central Register of Controlled Trials
(CENTRAL)
– Cost-effectiveness, eg: NHS Economic Evaluation Database
(NHS EED); Health Economic Evaluations Database
(HEED)
Identifying the sources to search (2)
• Databases
– MEDLINE, EMBASE, CINAHL, PsycINFO, AMED, HMIC
• Searchable e-journal packages
– Science Direct, Ingenta, Journals@Ovid
• Registers of Research
– mRCT, National Research Register, cancer.gov
• Conference Proceedings
– Index to Conference Proceedings, ISI Proceedings
• Dissertations
– Digital Dissertations, Index to Theses
• Interested parties
– Professional associations, voluntary groups
• Internet ….
Searching information sources effectively
• Translating the parts of the question (PICO) into
search terms
• Combining search terms using Boolean logic
• Sensitivity vs precision
• Sensitivity maximising
–
–
–
–
Synonyms
Subject headings and free-text
Truncation and wildcards ($, ?, *)
Proximity operators (adj, near, same)
• Search filters, quality filters
A search strategy
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Alcoholism/
Alcohol drinking/
alcoholic?
P
alcoholism.tw
dipsomania$.tw
or/1-5
Taurine/
acamprosate.tw
campral$.tw.
or/7-9
11.
12.
13.
14.
15.
16.
17.
18.
Naltrexone/
naltrexone.tw
trexan.tw
or/11-13
Temperance/
temperance.tw
sobriety.tw
((control$ or reduc$ or
restrict$) adj2 drink$).tw
19. or/15-18
20. 6 and 10 and 14 and 19
Challenges of the role
•
•
•
•
Publication bias
Time vs quality trade-off
Complexity of review questions
Widening perspectives
References
Alderson P, Green S, Higgins JPT eds. Cochrane Reviewers’ handbook
4.2.2. [updated March 2004]. Available from
<www.cochrane.org/resources/handbook/hbook.htm> [Accessed 11 October
2004].
Booth A and Fry-Smith A. 2003. Developing the research question. In: Etext
on Health Technology Assessment (HTA) information resources, Available
from Internet <URL: http://www.nlm.nih.gov/nichsr/ehta/chapter1.html>,
[Accessed 14 March 2003].
Booth A, O'Rourke AJ, Ford NJ. 2000. Structuring the pre-search reference
interview: a useful technique for handling clinical questions. Bull Med Libr
Assoc 88(3):239-46.
Chalmers I and Altman DG eds. 1995. Systematic reviews. London, BMJ
Publishing Group.
Counsell C. 1997. Formulating questions and locating primary studies for
inclusion in systematic reviews. Annals of Internal Medicine, 127(5), 380387.
References
INAHTA. 2000. INAHTA: International Network of Agencies for Health
Technology Assessment: global networking for effective healthcare,
Stockholm, INAHTA.
McKibbon A. 1999. PDQ evidence-based principles and practice. Hamilton,
Ontario: BC Decker Inc.
Mulrow C. 1995. Rationale for systematic reviews. In: Chalmers I and
Altman DG eds. Systematic reviews. London, BMJ Publishing Group.
Oxman AD, Sackett DL and Guyatt GH. 1993. Users' guides to the medical
literature. I. How to get started. The Evidence-Based Medicine Working
Group. JAMA, 270(17), 2093-2095.
Richardson WS, Wilson MC, Nishikawa J and Hayward RS. 1995. The wellbuilt clinical question: a key to evidence-based decisions. ACP Journal Club,
123(3), A12-A13.
References
Sacket DL, Richardson WS, Rosenbery W, Haynes RB. 1997. Evidencebased medicine. How to practice and teach EBM. 1st ed. London: Churchill
Livingston, 1997.
Snowball R. 2002. 'Find the evidence'--reflections on an information skills
course for community-based clinical health-care staff at the Cairns Library,
Oxford. Health Information & Libraries Journal, 19(2), 109-112.
Song F, Eastwood AJ, Gilbody S, Duley L and Sutton AJ. 2000. Publication
and related bias. Health Technol Assess, 4 (10).
Villanueva EV, Burrows EA, Fennessy PA, Rajendran M and Anderson JN.
2001. Improving question formulation for use in evidence appraisal in a
tertiary care setting: a randomised controlled trial. BMC Medical Informatics
and Decision Making, 1(1), 4.
Janette Boynton
Senior Health Information Scientist
0141 225 6982
[email protected]