What is the Cochrane Collaboration?

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Archie Cochrane (1909-1988)

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“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 randomized controlled trials”.

Archie Cochrane, 1979

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Collaboration’s Mission Statement

The Cochrane Collaboration is a unique worldwide organization that aims to help people make well informed decisions about health care by preparing, maintaining and promoting the accessibility of

systematic reviews of the effects of health care interventions.

www.cochrane.org

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Centres12

Networks

Methods Groups

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Fields16

Steering Group

Structure of The Cochrane Collaboration

Review Groups52

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Cochrane Centres

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Cochrane Review Groups

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• International group of experts with an interest in a health problem area

• Prepare and maintain systematic reviews

• Willing and able to review all relevant research on health care problems related to their area

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• Back

• Effective Practice and Organization of Care

• Hypertension

• Inflammatory Bowel Disease and Functional Bowel Disorders

• Musculoskeletal

• Upper Gastrointestinal and Pancreatic Diseases

Cochrane Review Groups

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Worldwide there are 52 registered review groups,6 of which have their editorial base in Canada

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10 Key Principles

….guide the work of Cochranites

1. Collaboration …good communication, open decision-making and teamwork.

2. Building on the enthusiasm of individuals …involving and supporting people based on interest and including consumers.

10 Key Principles (cont)

3. Avoiding duplication …maximise efficiency, one review is enough.

4. Minimising bias …scientific rigour, broad participation, and avoiding conflicts of interest.

5. Keeping up-to-date …up-dating reviews by identifying and adding new trials at least every 2 years.

10 Key Principles (cont)

6. Ensuring relevance …choosing outcomes that matter to patients.

7. Ensuring access …wide dissemination ...appropriate price, content and medium to meet needs of users worldwide.

8. Quality improvement …improving methodology, encouraging feedback and criticism and responding to it.

10 Key Principles (cont)

9. Ensuring continuity …responsibility for reviews, editing, and key functions is maintained and renewed.

10. Enabling wide participation …announced at the 8th Colloquium 2000 in Cape Town, South Africa

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www.thecochranelibrary.com

New Editor-in-Chief: Dr. David Tovey

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What is The Cochrane Library?

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- Main output of Cochrane Collaboration

- Contains Cochrane reviews & other databases

www.thecochranelibrary.com

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The Cochrane Library

Search takes place every second

Abstract is viewed every 2 seconds

Full text review is downloaded every 3 seconds.

2013 Impact Factor 5.939

2013 Hypertension Group impact factor 5.765 A review published in 2011 or 2012 was cited, on average 5.765 times in 2013.

Cochrane LibraryNovember, 2014

6126 systematic reviews 2544 protocols (reviews in preparation) >23,000 abstracts of non-Cochrane systematic reviews > 600,000 controlled clinical trials Excellent search engine.

Systematic Review

Definition: A concise summary of the best available evidence that addresses a sharply defined clinical question and attempts to answer it using explicit and rigorous methods to identify, critically appraise and synthesize all relevant studies.

Only uses scientifically valid evidence. Evidence-based is synonymous with scientifically valid.

Thomas C Chalmers (1917-1995)

Thomas C Chalmers

Outspoken advocate for “randomized controlled trials”.

“Randomize the first patient”

“In the absence of good evidence it is unethical to treat patients with an unproven intervention except in a randomised clinical trial comparing the new intervention with standard therapy.”

Paradigm (mind-set) for decision to administer or take an intervention

In the absence of good evidence (science), give an intervention only as part of an RCT.

Otherwise use interventions where the benefits have been proven to outweigh the harms in a systematic review of RCTs.

Intervention in the absence of evidence = “snake oil” Many health interventions are scientifically unproven and

thus no different from “snake oil”

Ways to Get Involved

Author, peer reviewer Provide feedback to reviews Handsearcher Methods Group Disseminate findings Consumer Network

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R E G I S T E R I N G A T I T L E

Introduction to Cochrane systematic

reviews

Things to keep in mind when designing a research question

Primary aim should be to summarize and help people understand the evidence

Careful not to impose own values and preferences (minimize bias)

Help people make a practical decision about a health care decision

Easy to read and understand by someone who is not an expert in the area.

Use ‘PICOS’ to define the question

•Participants – Describe the specific patient population characteristics and/or context of the condition or disease.

•Intervention – Define the intervention(s).

•Comparison – Define the control intervention.

•Outcome – Define the outcomes of interest from the most important to the least

•Study Design – Define the type of study that is acceptable to answer this question RCTs?, quasi-RCTs?, non-RCTs?

Exercise

Authors have approached us to register a title to study ACE inhibitors versus Angiotensin receptor blockers to prevent stroke.

Create a systematic review question (PICOS) for this review and provide advice as to which Cochrane Review Group should register the title.

ACE inhibitors vs ARBs

Patients. Hypertension

Intervention. ACE inhibitors

Control. ARBs

Outcome. Mortality and morbidity including fatal and non-fatal stroke

Study design. RCTs

(Hypertension Group)

ACE inhibitors vs ARBs

Patients. Stroke or TIA in last year

Intervention. ACE inhibitors

Control. ARBs

Outcome. Mortality and morbidity including fatal and non-fatal stroke

Study design. RCTs

(Stroke Group)

Title registration

a title will be registered if: it is within the defined scope of the CRG

it is not already taken

it addresses a reasonable question

complete the Title Registration Form which you will receive from the CRG

Funding of Cochrane Reviews

Many organizations provide funding for systematic reviews

Include research funding agencies, those providing or funding health care services

Cannot be funded through a commercial source or agency with a vested interest in reviews

Handbook Chapter 2.6

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Advantages of a Cochrane review

Rigour of methodology

Broad scope of literature included

Updated and maintained

Inclusiveness of perspectives

Plain language summary

Independence from commercial interests

Risk of bias is estimated and included in the interpretation of the evidence

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Guidelines for Protocol and Review Process

6 Months

Title RegistrationApproval of title by

Editorial Board

Protocol SubmissionIf no protocol, registered title

becomesavailable to other interested

reviewers

1.5 Years

Review SubmissionIf no review, registered

title becomes available to others

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Steps in doing Systematic Review

Identifying a question (PICOS)

Registering the Title

Writing the protocol

Search to find all trials (Cochrane Library etc)

Choosing and entering relevant trials

Characteristics of included and excluded trials

Steps in doing Systematic Review (cont)

Risk of bias of included trials

Extracting and entering data

Interpreting findings (subgroup analysis, sensitivity analysis)

Writing results and discussion

Summary of Findings Table, conclusions and abstract

Submit review for publication

L I F E I S F U L L O F T R I A L S .

What have I learnedfrom the Cochrane Collaboration?

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C O M P R E S S I O N S T O C K I N G S F O R P R E V E N T I N G D E E P V E I N T H R O M B O S I S I N A I R L I N E

PA S S E N G E R S .

A Cochrane Systematic Review

Compression stockings for preventing deep vein thrombosis in airline passengers

Air travel might increase the risk of deep vein thrombosis (DVT). It has been suggested that wearing compression stockings might reduce this risk.

ObjectivesTo assess the effects of wearing compression stockings versus not wearing them among people travelling on flights lasting at least four hours.

Search methodsThe Cochrane Peripheral Vascular Diseases Group searched their Specialized Register (last searched April 2007) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (inception to Issue 1, 2007). The authors searched MEDLINE (January 1966 to November 2005), EMBASE (January 1980 to December 2005) and several other electronic or grey literature sources, detailed in full in the review.

Exercise

SEARCH THE COCHRANE LIBRARY TO FIND OUT WHETHER ACE

INHIBITORS OR ARBS ARE BETTER FOR TREATING PATIENTS

WITH HYPERTENSION.

Selection criteriaRandomized trials of compression stockings versus no stockings in passengers on flights lasting at least four hours. Trials in which passengers wore a stocking on one leg but not the other, or those comparing stockings and another intervention were also eligible.

Data collection and analysisAt least two authors independently assessed the quality of each study and extracted data. We sought additional information from trialists.

Main resultsTen randomized trials (n = 2856) were included; nine (n = 2821) compared wearing stockings on both legs versus not wearing them, and one (n = 35) compared wearing a stocking on one leg for the outbound flight and on the other leg on the return flight. Of the nine trials, seven included people judged to be at low or medium risk (n = 1548) and two included high risk participants (n = 1273). All flights lasted at least seven hours.

Main results (cont)

Fifty of 2637 participants with follow-up data available in the trials of wearing stockings on both legs had a symptomless DVT; three wore stockings, 47 did not (odds ratio 0.10, 95% confidence interval 0.04 to 0.25, P < 0.00001). There were no symptomless DVTs in three trials. No deaths, pulmonary emboli or symptomatic DVTs were reported. Wearing stockings had a significant impact in reducing oedema (based on six trials). No significant adverse effects were reported.

Authors' conclusions

Airline passengers similar to those in this review can expect a substantial reduction in the incidence of symptomless DVT and leg oedema if they wear compression stockings. We cannot assess the effect of wearing stockings on death, pulmonary embolus or symptomatic DVT because no such events occurred in these trials. Randomized trials to assess these outcomes would need to include a very large number of people.