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Finding Evidence Based Clinical Information in the Cochrane Library and PubMed

EAHIL Continuing Education CourseHelsinki June 24th. 2008.Hilde Strømme, Ullevaal University Hospital, Medical Library

Finding Evidence Based Clinical Information in the Cochrane Library and PubMed.

EAHIL CEC, Helsinki, June 24th. 2008.Hilde Strømme, Ullevaal University Hospital, Medical Library.

Program

Introduction about questions Demonstration: PubMed Clinical Queries

and PubMed MeSH database Hands-on exercises in PubMed Demonstration: The Cochrane Library Hands-on exercises in The Cochrane

Library



The 5 steps in Evidence Based Practice

1. Ask a question

2. Find information/evidence to answer question

3. Critically appraise the information/evidence

4. Integrate appraised evidence with own clinical expertise and patient’s preferences

5. Evaluate



Examples of Questions

Is the Cage Questionnaire a good tool to diagnose alcoholism?

Is acupuncture effective for smoking cessation?

Can pressure relieving mattresses prevent pressure ulcers?

Can measels-mumps-rubella vaccine (MMR) cause autism?

In primary nocturnal enuresis in children, do alarm systems compared with pharmacological therapies produce fewer wet beds in the short term and the long term?

Will the quality of literature searches performed by health personnel improve if they have guidance from a librarian?



PICO:The components of a clinical question

P I C OPopulationPatientProblem

Interventionor Exposure

Comparison Outcome

Who are the patients?What is the problem?

What do we do to them?What are they exposed to?

What do we compare the intervention with?Not always necessary.

What happens?What is the outcome?



In primary nocturnal enuresis in children, do alarm systems compared with pharmacological therapies produce fewer wet beds in the short term and the long term?

P I C O

PopulationPatientProblem


Comparison Outcome

Nocturnal enuresis in children

Alarm systems

Fewer wet beds

Pharmacological therapies



PICO and Search Terms

P I C ONocturnal enuresis in children

Alarm systems Pharmalogical therapies

nocturnal enuresisbedwettingnighttime urinary incontinence

alarm* antidiuretic agentsdesmopressinimipramineO

R

AND



P I C O

PopulationPatientProblem


Comparison Outcome

Children AutismMMR vaccine

Can measels-mumps-rubella vaccine (MMR vaccine) cause autism?

(No vaccine)



PICO and Search Terms

P I C OChildren

MMR vaccine Autism

Measles-Mumps-Rubella Vaccine MMR Vaccine Mumps Measles Rubella Vaccine Virivac Pluserix Priorix Trimovax Triviraten Berna

AutismAutistic disorderKanner’s Syndrome (Asperger Sydrome)

OR

AND



RCT

Cohort Studies

Case Control Studies

Cross Sectional Studies

Case Series

Case Report

Ideas, Editorials, Opinions

Animal research

In vitro (’test tube’) research

Systematic review

Evidence Pyramid



Systematic Review vs. Review Article Systematic Review

Identify, compare and summarize ALL relevant studies As close to objective as we get

Review Article Compare and summarize SOME relevant

studies May be biased

Question Study design Resources/Databases

Diagnosis Cross Sectional 1. DARE + HTA (in The Cochrane Library)2. Medline, EMBASE (and others)

Prognosis Cohort 1. DARE + HTA (in The Cochrane Library)2. Medline, EMBASE (and others)

Etiology CohortCase ControlCase Series

For questions about adverse effects:1. DARE + HTA (in The Cochrane Library)For other etiology questions:1. Medline, EMBASE (and others)

Effects(Therapy, prevention)

Randomised Controlled TrialControlled TrialCohortCase Control

1. Cochrane Database of Systematic Reviews, HTA og DARE (in The Cochrane Library), Clinical Evidence, Joanna Briggs, PEDro

2. CENTRAL (in The Cochrane Library)3. Medline, EMBASE (and others)

Experience

Qualitative Studies 1. Cinahl2. Medline (and others)

Relevant databases



Other relevant databases

DynaMed UpToDate Cinahl British Nursing Index PsycINFO AMED SveMed+ …..



Clinical Queries in PubMedUse Clinical Queries to limit your search to the appropriate study design

Or to find systematic reviews



Clinical Queries– what happens behind the scenes?

A search filter is added to your subject search, based on the type of question (therapy, diagnosis etc.)

The search filter is based on MeSH headings and text words describing the study design

Choose between broad and sensitive search (sensitivity) narrow and specific search (specificity)

Lena Nordheim, 2007

Build your MeSH-search by sending MeSH-terms to the Search Box and then click Search PubMed



MeSH or text words?

Using MeSH search will produce relevant hits, but you risk loosing some

The best is a combination of MeSH terms and text words. Reasons: The newest references have no MeSH yet

Indexing with MeSH is done by humans, humans make mistakes



Hands-On Exercises!

PICO forms: Identify the different components of the

question Decide what type of question it is Find search terms and write them in the

appropriate boxes of the form



Hands-On Exercises!

PubMed Clinical Queries Use the search terms to search PubMed Clinical

Queries Try both text words and MeSH database Look at the results – are the results relevant?



The Cochrane Library

The Cochrane Database of Systematic Reviews (CDSR or Cochrane Reviews)

Database of Abstracts of Reviews of Effects (DARE or Other Reviews)

Health Technology Assessment Database(HTA or Technology Assessments)

Cochrane Central Register of Controlled Trials (CENTRAL og Clinical Trials)



Search tips

Phrases: Words that belong together:use NEXT or quotation marks common NEXT cold ”common cold”

Beware: When you use qoutation marks, truncation will not work

Use NEAR for words that should occur close to each other (within 6 words) wound* NEAR infect*



More search tips

Truncation:infect* = infection, infections, infectious etc. *natal = prenatal, postnatal, perinatal etc.

Masking:hyp*tension = hypotension, hypertension



Even more search tips

Always use Advanced Search Make sure to search for ALL relevant

synonyms Tip: Use MeSH database in PubMed to find

synonyms

Search in ”Title, Abstract or Keywords” Will probably produce the most relevant hits



MeSH search – Be careful!

If you ONLY use MeSH search: You will not get the newest Cochrane reviews In Clinical Trials you will only get Medline-

references

Solutions: Combination of MeSH search and text-word

search Include the MeSH-term as one of your text-

words



Use Advanced Search to search for all synonymsTitle, Abstract or Keywords will probably produce the most relevant hits.



Combine Searches in Search History



Hands-On Exercises!

PICO forms: Identify the different components of the

question Decide what type of question it is Find search terms and write them in the

appropriate boxes of the form – use MeSH database in PubMed to find synonyms!



Hands-On Exercises!

The Cochrane Library Use Advanced Search to search for all relevant

synonyms Look at the results

Are there any relevant systematic reviews in Cochrane Reviews, Other Reviews or Technology Assessments?

Are there any relevant RCTs in Clinical Trials?

Exercises 4-8 are suitable for The Cochrane Library

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