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“Extreme searching”: How to conduct a systematic search in MEDLINEGenevieve Gore• Liaison [email protected] • 514 398 3472
Martin Morris • Liaison [email protected] • 514 398 8140
Schulich Library of Science and Engineering
???By the end of today’s class, you will:► Understand what MEDLINE is► Identify subject headings► Construct a search strategy► Run your search using MEDLINE on Ovid
OBJECTIVES
???A review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyse data from the studies that are included in the review.
What’s a systematic review?
From: Cochrane Collaboration (2014). Glossary: Systematic Review. Accessed Jun 25, 2014 http://www.cochrane.org/glossary/5#term423
???► One form of research synthesis► Other research synthesis
methods include:► Health technology assessments► Mixed studies reviews► Rapid reviews► Realist reviews► Scoping reviews…
What's a systematic review?
??? From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
Flow of information through the different phases of a systematic review
???Systematic reviews of interventions require a thorough, objective and reproducible search of a range of sources to identify as many relevant studies as possible (within resource limits).
What's a systematic search?
From: Cochrane Handbook (2011). Section 6.1.1.2. Minimizing bias. Accessed Jun 25, 2014: http://www.cochrane-handbook.org/
???1. Develop a research question2. Identify databases, search engines, trial
registries, etc. in which to run your search3. Develop a search strategy4. Run the search in your first database5. Apply filters6. Export references to a citation manager7. Translate and run the search in your
subsequent databases
How to find articles
Develop a Research Question
???You’re applying for a grant to support your research on infections in rheumatoid arthritis patientsThink of a question related to this topic...
Scenario
???Relevancy
Retrieval(# of search results)
Broad Questions
Narrow Questions
High = lots of articles
Low = very few articles
High = directly relevant articles
Low = mostly irrelevant articles
How questions influence search results
???Broad:► What is the prevalence of serious infections in
arthritis patients? Narrow:► What is the risk of tuberculosis for rheumatoid
arthritis patients treated with TNF alpha antagonists?
Very Narrow:► What is the annual incidence of Caplan’s
Syndrome for asbestos workers in Quebec?
Possible Questions
???Our Question Today
What is the risk of tuberculosis for rheumatoid arthritis patients treated with TNF alpha antagonists?
???► Consult library subject guideshttp://www.mcgill.ca/library/find/subjects/health
► Talk to a librarian
Decide where to search
???► MEDLINE:
What We Are Searching Today
► Biomedical database containing bibliographic information (doesn’t search full-text)
► Over 22 million references, mostly of articles
► Can be searched via PubMed or other platforms like Ovid (we will use the latter)
► Uses MeSH (subject headings), a controlled, hierarchical vocabulary used to consistently describe the subject of articles included in MEDLINE and to facilitate their retrieval
MEDLINE, PubMed, and PMC (PubMed Central): How are they different? https://www.nlm.nih.gov/pubs/factsheets/dif_med_pub.html
???Use the MEDLINE (Ovid) link on the Library site:http://www.mcgill.ca/library/find/subjects/health
Accessing MEDLINE (Ovid)
Develop a Search Strategy
???1. Break your question down into concepts2. Identify subject headings for each concept3. Identify text words for each concept
► Tips: ► Use a "target article" to help identify search terms► Use a worksheet to keep track of your terms
Step-by-Step
???Which concepts are contained in the question:
Break into PICO concepts
What is the risk of tuberculosis for rheumatoid arthritis patients treated with TNF alpha antagonists?
???PICO Patients with rheumatoid arthritisTNF alpha antagonists
Risk of tuberculosis
PopulationIntervention or ExposureComparisonOutcome or endpoint
PICO
What is MeSH?
???Why bother with MeSH?
cancertumor(s)tumour(s
)neoplasm(s)neoplasti
c
Neoplasms/
There are 27,883 descriptors in 2016 MeSH
???poverty
Poverty/
social disparity
financially disadvantag
ed
poor
breadline
financial distress
extreme needsocial
inequitylow income
destitute
Another MeSH Example
???Dental FissuresRoot Caries
Dental Caries
Stomatognathic Diseases
Tooth Demineralization
Tooth Diseases
Dental Caries in MeSH
Special Techniques in MEDLINE on Ovid https://www.brainshark.com/wkovid/vu?pi=zFvzXHuX2z34XJz0&cmpid=Brainshark:MedlineSpecialTechniques
Which subject heading explodes?
???Which subject heading explodes?
???Identify MeSH terms for these three concepts using MEDLINE on Ovid.
Activity: Identify subject headings
P
I
C
O
Patients with rheumatoid arthritisTNF alpha antagonists
Risk of tuberculosis
???Example of a target article
Citation: Dixon WG, Hyrich KL, Watson KD, Lunt M, Galloway J, Ustianowski A, B S R B R Control Centre Consortium, Symmons DP, BSR Biologics Register. Drug-specific risk of tuberculosis in patients with rheumatoid arthritis treated with anti-TNF therapy: results from the British Society for Rheumatology Biologics Register (BSRBR). Ann Rheum Dis. 2010 Mar;69(3):522-8.
Artice title:“Drug-specific risk of tuberculosis in patients with rheumatoid arthritis treated with anti-TNF therapy: results from the British Society for Rheumatology Biologics Register (BSRBR)”
???Record in MEDLINE (Ovid)
???MeSH indexing used
??? AND AND
ORexp Arthritis, Rheumatoid/
Tumor Necrosis Factor-alpha/ exp Tuberculosis/
OR
Etanercept/ or Infliximab/ or Adalimumab/
Mycobacterium tuberculosis/
OR
.
OR
OR
Concept #1
Concept #2
Concept #3
Subject Headings
TextWords
Search strategy
BREAK – 15 mins
???AND directs the computer to search for every reference that contains all of the search terms specified. Each term must be present in every reference.
Boolean Operators: AND/OR
OR = tells the computer to retrieve every reference that has at least one of the search terms--all terms do not have to be present in every reference.
???Why? ► Not all citations have subject
headings► Indexers are only human (they
make mistakes)
Next: Identify Text Words
??? AND AND
ORexp Arthritis, Rheumatoid/
Tumor Necrosis Factor-alpha/ exp Tuberculosis/
OR
Etanercept/ or Infliximab/ or Adalimumab/ or Certolizumab Pegol/
Mycobacterium tuberculosis/
OR
Arthriti*.mp. (tumo?r necrosis factor a or tumo?r necrosis factor alpha or TNF A or TNF alpha or TNFA or TNFalpha).mp.
tuberculosis.mp.
OR (Biologic* or bdmard*).ti. TB.mp.
OR
(Etanercept or Infliximab or Adalimumab or certolizumab or czp or golimumab).mp.
Concept #1
Concept #2
Concept #3
Subject Headings
TextWords
Search strategy
???► Start with your first concept► Search for the subject headings first► Then search text words► Combine these synonymous searches
with OR using your search history► Repeat for your second, third,
and subsequent concepts► Finally, combine your different
concept sets with AND
How to search
Run the search
??? AND AND
ORexp Arthritis, Rheumatoid/
Tumor Necrosis Factor-alpha/ exp Tuberculosis/
OR
Etanercept/ or Infliximab/ or Adalimumab/ or Certolizumab Pegol/
Mycobacterium tuberculosis/
OR
Arthriti*.mp. (tumo?r necrosis factor a or tumo?r necrosis factor alpha or TNF A or TNF alpha or TNFA or TNFalpha).mp.
tuberculosis.mp.
OR (Biologic* or bdmard*).ti. TB.mp.
OR
(Etanercept or Infliximab or Adalimumab or certolizumab or czp or golimumab).mp.
Concept #1
Concept #2
Concept #3
Subject Headings
TextWords
Search strategy
Applying filters
???Common MEDLINE filters:1. Date of publication
► Only studies conducted between 2000 and 2015
► Should have a valid justification for it
2. Publication language► Only materials written in English
or French
Example Filters - Basic
???Apply to your combined search result set:
► English or French Language
Practice: Apply basic filters
???To play it safe, have your EndNote library already open
In Ovid Online: Export in batches of <= 1000
???Save your Ovid search
Select only one record to avoid creating a huge Word document!
The point here is not to save the records, but rather the search strategy
http://screencast.com/t/r98iRkZZa86w
???► Retain as much of your original strategy as possible
► Recognize that subject headings will be different (or non-existent)
► Keep track of your search terms using new worksheets
Moving to other databases
EMBASE example
Search one database at a time to take advantage of
subject headings
???Export References to a Citation Manager
Available to McGill students, faculty, staff.
Available to McGill students, faculty, staff.
???What they do:► Identify and remove duplicate references► Format your bibliography► Organize references into groups► Share your references with colleagues► Automatically find full-text articles► Provide location for article screening
Information and workshops: http://www.mcgill.ca/library/services/citation/software
Citation Managers
Export to EndNote
???Remove duplicates
https://www.flickr.com/photos/fortcollinschiropractor/6169824610
Next steps
??? From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
Next steps
???► Snowball searching► Grey literature► Hand searching
Other ways of identifying studies
???Document your search
???#7) Describe all information sources (e.g. databases with dates of coverage, contact with study authors to identify additional studies) in the search and date last searched.
#8) Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated.
PRISMA Checklist for Reporting Systematic Reviews
From: PRISMA Statement for Reporting Systematic Reviews (2012). PRISMA Checklist. Accessed Jun 25, 2014: http://www.prisma-statement.org/
???
Next steps
??? From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
Next steps
Nazi Torabi514 398 8087
Genevieve Gore
514 398 3472genevieve.gor
Martin Morris514 398 8140martin.morris
@mcgill.ca
Anesthesia, Cardiology, Dermatology, Endocrinology & Metabolism, Gastroenterology, Hematology, Internal Medicine, Medical Education, Nephrology, Neurology & Neurosurgery, Obstetrics & Gynecology, Oncology, Ophthalmology, Orthopedics, Otolaryngology, Respiratory Medicine, Surgery, Undergraduate Medicine, UrologyEpidemiology, Family Medicine, Infectious Diseases, Occupational Heath, Pediatrics, Public Health
Clinical & Health Informatics, Dentistry, Diagnostic Radiology, Emergency Medicine, Experimental Medicine, Geriatric Medicine, Indigenous Health, Medical Physics, Palliative Care, Pathology
???Systematic review guidelines:
Systematic Reviews: A Guide to Library Resources at McGillhttp://wikisites.mcgill.ca/systematicreview/index.php/Main_Page
PRISMA (Preferred Reporting Items of Systematic Reviews and Meta-Analyses) http://www.prisma-statement.org/statement.htm
Citation management:
Getting help with EndNotehttp://www.mcgill.ca/library/services/citation/software/endnote
Resources
???Additional references
1. Chan A-W. Out of sight but not out of mind: how to search for unpublished clinical trial evidence. BMJ 2012;344:d8013.
2. Rethlefsen ML, Murad M, Livingston EH. Engaging medical librarians to improve the quality of review articles. JAMA. 2014;312(10):999-1000.
3. Hausner E, Guddat C, Hermanns T, Lampert U, Waffenschmidt S. Development of search strategies for systematic reviews: validation showed the noninferiority of the objective approach. J Clin Epidemiol. 2015;68(2):191-9.
4. Mahood Q, Eerd DV, Irvin E. Searching for grey literature for systematic reviews: challenges and benefits. Res Synth Methods. 2014;5(3):221-34.
5. McGowan J, Sampson M, Lefebvre C. An evidence based checklist for the peer review of electronic search strategies (PRESS EBC). Evid Based Lib Info Practi 2010;5(1):149-54.
6. McGowan J, Sampson M. Systematic reviews need systematic searchers. J Med Libr Assoc 2005;93(1):74-80.
7. Preston L, Carroll C, Gardois P, Paisley S, Kaltenthaler E. Improving search efficiency for systematic reviews of diagnostic test accuracy: an exploratory study to assess the viability of limiting to MEDLINE, EMBASE and reference checking. Syst Rev. 2015;4:82.
8. Rader T, Mann M, Stansfield C, Cooper C, Sampson M. Methods for documenting systematic review searches: a discussion of common issues. Res Synth Methods. 2014;5(2):98-115.
9. Sampson M, McGowan J. Errors in search strategies were identified by type and frequency. J Clin Epidemiol 2006;59(10):1057-63.
10. Waffenschmidt S, Guddat C. Searches for randomized controlled trials of drugs in MEDLINE and EMBASE using only generic drug names compared with searches applied in current practice in systematic reviews. Res Synth Methods. 2015;6(2):188-94.
