A step by step Guide to Searching the

Cochrane database

www.knowledgenet.ashfordstpeters.nhs.uk/knet/

2011

KnowledgeNet www.knowledgenet.ashfordstpeters.nhs.uk/knet/

By the end of this presentation you will be able to:

• Run a simple search on the Cochrane Library using both free text and MeSH searching

• Work your way around a systematic review on the Cochrane Library

• Understand Boolean operators and truncation

Background

The Cochrane Library is the premier resource for information on the effectiveness of healthcare interventions. It is a collection of information put together by the Cochrane Collaboration, the Centre for Reviews and Dissemination and others. It is updated quarterly.

What is the Cochrane Library?

• A source of best evidence on effective treatments

• A source of systematic reviews

• A resource to support evidence based healthcare

The Cochrane Library

� The Cochrane Database of Systematic Reviews - Full text of systematic reviews published by the Cochrane Collaboration. Each review is updated at least every two years.

� Database of Abstracts of Reviews of Effects (DARE) - Summaries of systematic reviews from elsewhere in the literature (i.e. that are not Cochrane reviews).

� Central Register of Controlled Trials – Bibliographic references to randomised controlled trials. Not critically appraised.

� Database of Methodology Reviews – Contains full-text systematic reviews of methodological studies.

� Methodology Register – A bibliography of publications which report on methods used in the conduct of controlled trials.

� Health Technology Assessment Database – Details of projects and completed publications from health technology assessment organisations.

� NHS Economic Evaluation Database – Structured abstracts describing economic evaluations of health care interventions. Papers are included if they provide a comparison of treatments and examine both the costs and outcomes of the alternatives.

When would you search the Cochrane Library?

• what is the effective treatment of y

• what is the effective treatment of y in condition x

• is treatment y better than treatment z

When NOT to use the Cochrane Library

• General health care information: prognosis, causal, epidemiology...

• Statistics: incidence and prevalence

• Needs assessment studies

Hierarchy of evidence

Systematic Reviews

Randomised Control Trials

Cohort Studies

Case-Control Studies

Cross Sectional Surveys

Case Studies

STRONGSTRONG

WEAKWEAK

Worked example: will hypnotherapy help people to give up smoking?

Remember:

• Focus your search question(think of the key terms – treatment & disease)

• Use synonyms if necessary(think of similar terms to represent a concept)

• Use truncation if appropriateFor example: hypno* will search for:hypnotherapy, hypnotherapist, hypnosis

� You can search by various different ways: � Basic Search� Advanced Search� MeSH terms� Search by Topic� New Reviews� Updated Reviews� A-Z� By Review Group

www.thecochranelibrary.com

Type hypno* in the search area

Click on the Go button

Results of search for hypno*

Type next terms smoking cessation into the search area

Click to search

Next select the Search History button (this displays previous searches)

Results of search for smoking cessation

To combine the searches type #1 and #2 in the search box, then click on Go

To view the results of the combined search, click on the link

Results

Use PDF linkto print or save

Click on the tabs to move to a specific part of the review

Type in your different search terms in separate boxes and choose where you want them to appear, e.g. title, author etc then click on Search.

Search by Topic

MeSH

Use the Search History button to get back to the main search page

Select the MeSH button

Type a single term in thesearch box

Then select the Thesaurus button

Select the relevant MeSH term

1. Choose Explode or Search this term only?

2. Then view results or go to search history

Search this Term Only

Use Search This Term Only if you wish to limit your search to those documents in which your subject heading is considered the major point or focus of the article.

but

If a record was to have a narrower term added, but not your term, then it would not retrieve it.

Explode

If you choose ‘Explode’ you will retrieve citations using the selected term and all of its more specific terms e.g.

If you enter ‘back pain’ and explode the term you will also retrieve those records which use the term ‘low back pain’

Select the Search History button to continue your search

Choose MeSH Search again and type the next term in the search field.

Select the Thesaurus button

Select the most appropriate MeSHheading from the list.

This time leave the default option to Explode then ‘View Results’ on next page click on Search History as before.

Combine searches together and click on link for results as before

To sum up:

• The Cochrane Library is helpful in answering very specific types of questions about effectiveness of interventions

• Vague effectiveness questions need to be reformulated to focus in on the treatment and disease

• Many questions are better answered by using more appropriate databases because the questions are not effectiveness questions

Glossary

• Review : is an attempt to synthesise the results & conclusions of 2 or more publications on a given topic.

• Systematic Review : is a review that strives comprehensively to identify and synthesise all the literature on a given topic (sometimes called an overview).

• Meta-analysis : a statistical technique for assembling the results of several studies in a review into a single numeric estimate.

Systematic reviews are...

an increasingly important source of evidence about the effects of health care because:

• They help decision makers to cope with the volume of of literature by summarising it.

• They provide ‘new’ information which may not be apparent from individual studies where the effects under investigation are small.