PICO search strategies

Techniques and tips to answer well-developed clinical

questions using EmbaseWednesday, 22 April 2015

Maura Sostack, MLS, AHIP

EBM Librarian

Evidence-Based Medicine Center

Clinical Solutions

Elsevier Health Sciences

Learning Objectives

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Describe the three concepts that form the basis of a PICO

search strategy.

Create search filters using natural language words and

phrases and controlled vocabulary terms.

Identify study type with its corresponding PICO question.

Table of Contents

Deconstruct a protocol

PICO search strategy

The building blocks of a PICO search

Use Embase to answer a well-developed prognosis PICO

question

Summary

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DECONSTRUCT A PROTOCOL

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EBM Center Protocol: title page

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EBM Center Protocol: table of contents

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EBM Center Protocol: PICO question

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EBM Center Protocol: study eligibility

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EBM Center Protocol: exclusion criteria

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Protocol: search strategy

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PICO SEARCH STRATEGY

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PICO search strategy

A number of our PICO search strategies are comprised of three

sets of separate and distinct controlled vocabulary and natural

language terms:

• Terms for the health condition of the patient(s) or

population=P

• Terms for intervention(s)=I

• Terms for study type(s).

PICO search strategy : step by step

• Create P and I search strings.

• Use the Boolean operator AND to create a P&I search string set.

• Create a study specific search string or, if applicable, use a validated study

hedge.

• Use the Boolean operator AND to combine the study string set(s) with the P & I

set.

• Use the NOT Boolean operator to remove non-essential publication types and

animal studies.

• To reflect continuous updating, use the AND Boolean operator to add the ‘since

date’ search string to create the search of record.

PICO search strategy : caveat

Generally speaking, it is inadvisable to search on every

aspect of the clinical question within the confines of one

search strategy session.

THE BUILDING BLOCKS OF A PICO

SEARCH

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What’s in a name? Hedges; optimal filters; quality filters;

evidence-based filters=search strings

• Hedges and filters are search strings that contain controlled vocabulary

(EMTREE, MeSH, etc.) and natural language words and phrases.

• A validated hedge or filter contains both controlled vocabulary and natural

language words and phrases and has been put through a formal validation

process.

• Validated and un-validated hedges and filters are used to search for

American and British spelling of concepts and terms and to find incorrectly

indexed and e-pub ahead of print citations.

• Sets are created within the database interface when these hedges and

filters are used.

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Hedges and filters: +/∆

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+ ∆Hedges, filters Control

Ensure retrieval of e-pub

ahead of print and online

first citations

Incorrectly indexed

citations

Complex and require

deep understanding of

basic & advanced search

techniques

Require time to develop

Require time to validate

Hedges, filters, & search term resources

McMaster University Health Information Research Unit (HIRU) Hedge Project:

http://hiru.mcmaster.ca/hiru/HIRU_Hedges_home.aspx

The InterTASC Information Specialists' Sub-Group Search Filter Resource:

https://sites.google.com/a/york.ac.uk/issg-search-filters-resource/

University of Pittsburgh MedTerm Search Assist:

http://www.hsls.pitt.edu/terms/

HLWIKI International: http://hlwiki.slais.ubc.ca/index.php/Filters_(ie._hedges)

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Question type Question definition Study methodology Embase study string

Diagnosis Diagnosis: the nature of

a disease; the

identification of an

illness.

Prospective, blind comparison

to a gold standard

(‘sensitivity and specificity'/de ) OR

(specificity:ab,ti )OR ('sensitivity and

specificity':ab,ti)

Prevention Prevention: to avert,

avoid or prevent the

onset of disease.

Randomized Controlled Trial

(RCT)

random*:ab,ti AND trial*:ab,ti OR

'randomized controlled trial'/de

Prognosis Prognosis: The forecast

of the probable outcome

or course of a disease;

the patient's chance of

recovery.

Prospective cohort; case-

control; case series

'incidence'/de OR 'mortality'/de OR

'follow up'/de OR 'prognosis'/de OR

'prediction and forecasting'/exp OR

'cohort analysis'/exp OR

incidence:ab,ti OR mortality:ab,ti OR

'follow up':ab,ti OR prognos*:ab,ti

OR predict*:ab,ti OR cohort:ab,ti

Embase: EBM Center’s study filters

Question type Question definition Study methodology Embase study string

Therapy /

Treatment

Therapy: the treatment

of disease. Therapy is

synonymous with

treatment.

Randomized Control Trial

(RCT)

(random*:ab,ti AND trial*:ab,ti) OR

('randomized controlled trial'/de)

Harms A measure of patient

safety considering

errors or mistakes

which result in harm to

the patient.

Observational studies;

nationally representative

prospective cohort studies

with multivariate adjustment

of adverse effects.

multivar*:ab,ti OR adjust*:ab,ti OR

'multivariate analysis'/exp

Embase: EBM Center’s study filters

Embase: systematic review/meta-

analysis filter

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('meta analysis'/de OR 'metaanalyses':ti

OR 'metaanalysis':ti OR 'meta analysis':ti

OR 'meta analyses':ti OR 'systematic

review':ti OR 'systematic review'/de OR

'cochrane database of systematic

reviews':jt)

Embase: publication types

We use this search string to NOT out specific

publication types:

'letter'/de OR 'editorial'/de OR 'note'/de OR 'short

survey'/exp

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Embase: animal studies

We use this search string to eliminate animal

studies from search results:

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NOT ('animals'/exp NOT 'humans'/exp)

Embase: ‘since date’ for citation

indexing

Search string to limit citations by a specific

indexing date:

[11-4-2011]/sd

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Prognosis PICO

EBM Center Protocol: Prognosis PICO question

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Protocol: search strategy

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Prognosis PICO: P search strings

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Prognosis PICO: P & I search stings

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Prognosis PICO: study filter

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Prognosis PICO: NOT publications,

NOT animal studies and final results

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Search conducted on 7 April 2015

Prognosis PICO : combined harms, prognosis study

and systematic review/meta searches

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Search conducted on 21 April 2015

Prognosis PICO: study search of

record

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'community acquired infection'/de OR 'community acquired

infection':ab,ti OR 'community acquired disease':ab,ti AND

('pneumonia'/exp OR pneumonia:ab,ti) OR 'community acquired

pneumonia'/de OR 'community acquired pneumonia':ab,ti AND

('pneumonia outcomes research team':ab,ti OR port:ab,ti OR 'smart-

cop':ab,ti OR 'a-drop':ab,ti OR 'pneumonia severity index'/de OR

'pneumonia severity index':ab,ti OR 'psi':ab,ti OR 'curb 65 score':ab,ti

OR 'scoring system'/de) AND ('incidence'/de OR 'mortality'/de OR

'follow up'/de OR 'prognosis'/de OR 'prediction and forecasting'/exp

OR 'cohort analysis'/exp OR incidence:ab,ti OR mortality:ab,ti OR

'follow up':ab,ti OR prognos*:ab,ti OR predict*:ab,ti OR cohort:ab,ti)

NOT ('animal'/exp NOT 'human'/exp) NOT ('letter'/de OR 'book'/de OR

'editorial'/de OR 'note'/de OR 'short survey'/exp) AND [7-4-2011]/sd

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Prognosis PICO: harms search of

record

'community acquired infection'/de OR 'community acquired infection':ab,ti

OR 'community acquired disease':ab,ti AND ('pneumonia'/exp OR

pneumonia:ab,ti) OR 'community acquired pneumonia'/de OR 'community

acquired pneumonia':ab,ti AND ('pneumonia outcomes research

team':ab,ti OR port:ab,ti OR 'smart-cop':ab,ti OR 'a-drop':ab,ti OR

'pneumonia severity index'/de OR 'pneumonia severity index':ab,ti OR

'psi':ab,ti OR 'curb 65 score':ab,ti OR 'scoring system'/de) AND

(multivar*:ab,ti OR adjust*:ab,ti OR 'multivariate analysis'/exp) NOT

('letter'/de OR 'book'/de OR 'editorial'/de OR 'note'/de OR 'conference

paper'/de OR 'short survey'/exp OR 'conference abstract'/it) NOT

('animals'/exp NOT 'humans'/exp) AND [7-4-2011]/sd

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Prognosis PICO : systematic review and

meta-analysis study search of record

'community acquired infection'/de OR 'community acquired

infection':ab,ti OR 'community acquired disease':ab,ti AND

('pneumonia'/exp OR pneumonia:ab,ti) OR 'community acquired

pneumonia'/de OR 'community acquired pneumonia':ab,ti AND

('pneumonia outcomes research team':ab,ti OR port:ab,ti OR 'smart-

cop':ab,ti OR 'a-drop':ab,ti OR 'pneumonia severity index'/de OR

'pneumonia severity index':ab,ti OR 'psi':ab,ti OR 'curb 65

score':ab,ti OR 'scoring system'/de) AND ('meta analysis'/de OR

'metaanalyses':ti OR 'metaanalysis':ti OR 'meta analysis':ti OR 'meta

analyses':ti OR 'systematic review':ti OR 'systematic review'/de OR

'cochrane database of systematic reviews':jt) NOT ('animal'/exp

NOT 'human'/exp) NOT ('letter'/de OR 'book'/de OR 'editorial'/de OR

'note'/de OR 'short survey'/exp) AND [7-4-2011]/sd

Summary

Work with your investigators to:

• Identify terms and preferred filter methodology.

Deconstruct a protocol:

• Select the important concepts expressed in the P and I

portion of the PICO question.

Develop search strings:

• Use controlled vocabulary and natural language words

and phrases of British and American derivation to

construct search strings.

Use validated hedges:

• When applicable to your specific clinical question.

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THANK YOU!

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