FACET - European Journal of Cancer Care September 2003 slides available at: Systematic Reviews and the Cochrane

FACET - European Journal of Cancer CareSeptember 2003

slides available at: www.blackwellpublishing.com/journals/ecc

Systematic Reviews and the Cochrane Collaboration

MUNRO, A.J.1

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*Click on “View”; “Notes Page” for explanatory notes

Who was Archie Cochrane, and why

do we collaborate in his name?

He was a public health physician

whose ideas were ahead of their

time: he was sceptical about the

assumption that doctors always

knew best; he thought that

clinicians should justify their

decisions, rather than simply be

allowed to do whatever they felt

like.

Systematic Reviews and the Cochrane

Collaboration



Systematic Reviews and the Cochrane Collaboration (continued)

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Archie Cochrane




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The main problem identified by

Cochrane

“Inflation”: input rising much faster than output, costs of health care rising faster than any demonstrable improvements in health.

Care and cure contrasted: the opportunity cost of inflation in ‘cure’ sector is sub-standard services in the ‘care’ sector.

Solution:Make cure lean and efficient and there will be nourishment for care.




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The agenda set by Cochrane for assessing an intervention

• Effectiveness

- Does it work?

• Efficiency

- Is it good value for money?

• Evaluation

- Has it been properly tested?

• Equality

- Can it be made available for everyone?




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Evidence: problems of assembly and

assimilationOverload

• There are around 23,000 journals publishing 2,000,000 papers in biology and medicine each year.

• These are published in a variety of languages and types of journals.

• To keep up with the ten leading medical journals requires looking at 200 papers and 70 editorials per month - each paper takes 30 to 60 minutes to read in detail.

The paper mountain• The biomedical literature

produces a stack of papers growing at a rate of 2 km per year.

• 4 years’ worth is the height of Mount Everest.



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The nine values

• Collaboration

• Building on the enthusiasm of individuals

• Avoiding duplication

• Minimizing bias

• Keeping up to date

• Ensuring relevance

• Ensuring access

• Continually improving the quality of its work

• Continuity




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Components of the collaboration (1)

• Steering Group

• Collaborative review groups (CRGs)




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• Cochrane Centres

• Fields & Networks




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• Methods groups

• Consumer network




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What is the Cochrane Product?

The Cochrane Library

• Database of systematic reviews

- Reviews (1669)

- Protocols (1266)

• Register of controlled clinical trials (362,540)

• Database of abstracts of reviews of effectiveness (DARE) (4006)

• Health technology assessment database (3138)

• Cochrane methodology register (4553)

• Database of methodology reviews (16)

• NHS economic evaluation database (11,485)




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A Systematic Review

Systematic manual

searches of key journals

Computersied databases

Review of reference lists

of articles

Consultation with experts

Identify studies

Review for relevance

Relevant Not Relevant

Evaluate methodological

quality

Extract data

Analyase data

Draw conclusions

Reject

Search of personal

files



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How reliable?

• 1998 quality review

• 15/53 reviews had major

defects

• 9/53 evidence did not

support conclusions

• 12/53 conduct or

reporting unsatisfactory

• 12/53 problems with style




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Problems (1)

• Difficult to grasp the

structure and vocabulary

• Recruitment and retention

• Costs and charging for

library

• Consumer involvement

• Perceived Stalinism




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Problems (2)

• Publication/citation

• The mythical Albanian trial

and the law of diminishing

returns

• How do you assess

evidence concerning

interventions for which RCT

is inappropriate or

impossible (e.g. rare

tumours)?

• Old trials test obsolete

techniquesslides available at: www.blackwellpublishing.com/journals/ecc



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“Artze sind Überflussig”

(doctors are superfluous)




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Cochrane Collaboration –

the real product




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Web based resources

Much of the text used in this presentation has been adapted from the information available on the Cochrane Collaboration website.


http://www.cochrane.org/

• The Cochrane manual provides considerable detail about the organisation and methods of the collaboration: it can be downloaded from: http://www.cochrane.org/cochrane/cc-man.htm

• The Cochrane library can be found at: http://www.update-software.com/cochrane/ (access via this portal is limited, unless you or your institution have a password or gateway)

• If you are using a computer recognised as belonging to the UK NHS network you can access the full Cochrane library via: http://www.nelh.nhs.uk/cochrane.asp

• The Cochrane Reviewer’s handbook can be downloaded from: http://www.cochrane.org/cochrane/hbook

• The Cochrane Cancer Network website is at: http://www.canet.org/



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• Altman, D.G. (2001). Systematic reviews of evaluations of prognostic variables. Bmj (Clinical Research Ed.), 323: 224-8.

• Antman, E.M., Lau, J., Kupelnick, B. et al (1992). A comparison of results of meta-analyses of randomized control trials and recommendations of clinical experts. Treatments for myocardial infarction. Journal of the American Medical Association. 268: 240-8.

• Clarke, M. (2002). Commentary: searching for trials for systematic reviews: what difference does it make? International Journal of Epidemiology. 31: 123-4.

• Cochrane, A.L. (1989). Effectiveness and Efficiency: random reflections on health services. The Rock Carling Fellowship 1971. BMJ Books. London.

• Cochrane, A.L. & Blythe, M. (1989). One Man's Medicine: An Autobiography of Professor Archie Cochrane. BMJ Books. London.


Other sources of information



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• Deeks, J.J. (2001). Systematic reviews in health care: Systematic reviews of evaluations of diagnostic and screening tests. Bmj (Clinical Research Ed.). 323: 157-62.

• Dickersin, K. & Manheimer, E. (1998). The Cochrane Collaboration: evaluation of health care and services using systematic reviews of the results of randomized controlled trials. Clinical Obstetrics and Gynecology, 41: 315-31.

• Dixon-Woods, M., Fitzpatrick, R. & Roberts, K. (2001). Including qualitative research in systematic reviews: opportunities and problems. Journal of Evaluation in Clinical Practice. 7: 125-33.

• Easterbrook, P.J., Berlin, J.A., Gopalan, R. et al. (1991). Publication bias in clinical research. Lancet. 337: 867-72.

• Egger, M., Davey Smith, G. & Altman, D.G. (2001). Systematic Reviews in Health Care: meta-analysis in context. BMJ Books. London.



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• Egger, M., Juni, P., Bartlett, C. et al (2003). How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Empirical study. Health Technology Assessment (Winchester, England). 7: 1-76.

• Egger, M., Zellweger-Zahner, T., Schneider, M. et al (1997). Language bias in randomised controlled trials published in English and German. Lancet. 350: 326-9.

• Evans, D. & Pearson, A. (2001). Systematic reviews: gatekeepers of nursing knowledge. Journal of Clinical Nursing. 10: 593-9.

• Grimshaw, J.M., Shirran, L., Thomas, R., et al (2001). Changing provider behavior: an overview of systematic reviews of interventions. Medical Care. 39; II2-45.

• Juni, P., Altman, D.G. & Egger, M. (2001). Systematic reviews in health care: Assessing the quality of controlled clinical trials. Bmj (Clinical Research Ed.). 323: 42-6.



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• Juni, P., Holenstein, F., Sterne, J. et al. (2002). Direction and impact of language bias in meta-analyses of controlled trials: empirical study. International Journal of Epidemiology. 31: 115-23.

• Klassen, T.P., Wiebe, N., Russell, K. et al. (2002). Abstracts of randomized controlled trials presented at the society for pediatric research meeting: an example of publication bias. Archives of Pediatrics & Adolescent Medicine. 156: 474-9.

• Linde, K. & Willich, S.N. (2003). How objective are systematic reviews? Differences between reviews on complementary medicine. Journal of the Royal Society of Medicine. 96: 17-22.

• Macbeth, F. & Overgaard, J. (2002). Expert reviews, systematic reviews and meta-analyses. Radiotherapy and Oncology : Journal of the European Society For Therapeutic Radiology and Oncology. 64: 233-4.



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• Moher, D. & Schachter, H.M. (2002). Potential solutions to the problem of conducting systematic reviews of new health technologies. Canadian Medical Association Journal 166: 1674-5.

• Olsen, O., Middleton, P., Ezzo, J., Gotzsche, P.C., Hadhazy, V., Herxheimer, A., Kleijnen, J. & McIntosh, H. (2001). Quality of Cochrane reviews: assessment of sample from 1998. Bmj (Clinical Research Ed.). 323: 829-32.

• Petticrew, M. (2001). Systematic reviews from astronomy to zoology: myths and misconceptions. Bmj (Clinical Research Ed.). 322: 98-101.

• Rothwell, P.M. (2002). Why do clinicians sometimes find it difficult to use the results of systematic reviews in routine clinical practice? Evaluation and the Health Professions. 25: 200-9.



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• Shea, B., Moher, D., Graham, I. Et al. (2002). A comparison of the quality of Cochrane reviews and systematic reviews published in paper-based journals. Evaluation and the Health Professions. 25: 116-29.

• Silagy, C.A., Middleton, P. & Hopewell, S. (2002). Publishing protocols of systematic reviews: comparing what was done to what was planned. Journal of the American Medical Association. 287: 2831-4.

• Sterne, J.A., Egger, M. & Smith, G.D. (2001). Systematic reviews in health care: Investigating and dealing with publication and other biases in meta-analysis. Bmj (Clinical Research Ed.). 323: 101-5.

• Sutton, A.J., Duval, S.J., Tweedie, R.L. et al (2000). Empirical assessment of effect of publication bias on meta-analyses. Bmj (Clinical Research Ed.). 320: 1574-7.



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Documents

FACET - European Journal of Cancer Care September 2003 slides available at: Systematic Reviews and the Cochrane