literature review for clinical prediction rules cgmh slides

8/6/2019 Literature Review for Clinical Prediction Rules CGMH Slides

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Literature review workshop

for CPR group in CGMH ED

Kuan-Fu Chen!!

February 12, 2011



OutlineDatabases

Difference btw Pubmed vs. Ovid MEDLINE

MeSH heading Text word searching

Search process

Tips for Pubmed & Ovid MEDLINE

Trouble-shooting

Examples

Endnote



Databases

•"Pubmed

•"Ovid MEDLINE

•"UpToDate

•"Cochrane library

•"MDConsult

•"EMBASE

•"Google scholar



Difference btw

Pubmed vs. Ovid MEDLINEUse

If you want to learn a MEDLINE interface that will be always available to you, even if you

CGMH.

If you are off-campus and having

issues.

When you want quick results with strategies

created for you.

When you are looking for extremely

citations.

When you also want to search for

and

biology information.

Use Ovid

To be

through selections for a precise search based on Medical SubjectHeadings, subheadings, and limits.

To build a search strategy in

and by trying multiple

.



Difference btwPubmed vs. Ovid MEDLINE



MeSH heading

Medical Subject Headings

Maintained by National Library of Medicine (NLM)

Subheadings: tree or mapping

Pubmed: [Subheading]

MEDLINE: /su[ ]

If no picked, all selected



MeSH heading

Strength of MeSH

Secondary topic pre-linked to a MeSH term by an indexer

Standardization Aortic rupture vs. Ruptured aorta vs. Rupture of the thoracic aorta

Focus/major topic

Subheadings

Explode

Find MeSH below in the “tree”

Difference between Pubmed vs. Ovid MEDLINE



MeSH heading

Limitation

Not for all

Not for recent citations

Not every word in abstract

New MeSH not retroactive



Text word searching

Helpful if no MeSH term, and to supplement MeSH

Strength

Instant indexUp-to-date terminology

Every word in abstract searchable

Challenge

Easy to miss information

Different words for same topic

Can’t use Explode, Focus, or Subheadings



Text word searching

Searching for variations

Truncation character (*): Sep*

Synonyms: Sepsis, bacteremia

British spellings: Baecteremia

Break up phrases

Septic shock → sep* AND shock ($ = * # ? or #)

Search MeSH as major topic (focus) then scan results to see variation in titles

Display MeSH scope note

Pubmed: Entry Terms

Ovid MEDLINE: [i] in mapping or tree display; look for “used for” list



Search process (1/4)

Analyze the question

Identify critical topics, keeping only essential ones (fewest possible)

Search each topic separately

Most important topic first

Create separate result sets for MeSH and for text words

Why? Different thought processes:

MeSH

Use mapping; check Tree display to decide whether to explode

Make major topic (focus) decision

Check Subheadings for exact match to search topic.




Create separate result sets for MeSH and for text words (con’t)

Text words

Type synonyms,Use truncation character,

Different spellings, spacings, etc.

Combine word variations using OR

(RU486 or RU 486 or RU-486).

Be sure topics in text word search match topics in MeSH search.

If MeSH is major topic, search text words in title only (major point).




Combine set numbers

Use OR to combine words or set numbers expressing the

SAME TOPIC.! Computer merges results and eliminatesduplicates.

Use AND to combine words or set numbers expressingDIFFERENT topics Computer finds citations with both topics(or all, if >2)

Use parentheses to avoid logic errors

PubMed: (#6 OR #9) AND (#12 OR #15)!Ovid: 1 and (5 OR 8)




Too many irrelevant citations? -- Make one or more topics a major point(focus).

LIMIT to target large search results better:

Review articles

Core Clinical Journals – NEJM, JAMA, and other frequently-used journals

Valid clinical evidence limits: Publication Type = Randomized Controlled Trialor Meta Analysis, Clinical Queries, Subject Subset = Systematic Review

Search all MeSH and text word variations that match your topics.

Look at MeSH Headings assigned to the best results.

If see another good MeSH, add it to your search.



Tips-Ovid medline

Don’t forget to click the Advanced Ovid Search tab

Typing AND or OR turns off mapping, even if “Map

Term” box checked.

Select ONLY ONE MeSH from Mapping list/Tree display,or Subheadings list will be skipped.

Check Explode box to add narrower (indented) MeSH.Check Tree display before

exploding, so you know which MeSH will be added.



Tips-Ovid medline

Text word search

Type synonyms & word variations in search box, combined with OR.

E.g. autops* or post-mortem* or postmortem*

Typing “or” bypasses mapping and performs a “Multi-Purpose” (.mp.) search (title, abstract, etc.)

To search as major topic, click TITLE button before clicking [Search].

If Ovid “Can not map”, temporarily un-check “Map to MeSH” box, ORtype a field qualifier after the word: .mp. or .ti.



Tips-Ovid medline

Too many irrelevant citations?

Focus a previous MeSH set by typing an asterisk followed by the setnumber – e.g. *2

Convert a previous .mp. result to title search. Type set number with”.ti.” – e.g." 5.ti.

Combine again using new set numbers.

Full text: 1st try “Ovid Full Text” links. If none appears, click Get It forother Drexel full text options. Beware: “Limit to full text” options missmuch Drexel full text.

LOGOFF from OVID to release the session and permit others to log in.



Tips-Pubmed

For each topic return to MeSH Database to map to MeSH.

Add text words using PubMed’s default/basic search.

Default search retrieves from all parts

(“fields”) of a citation, including text words.

Asterisk (truncation character) prevents mapping to

MeSH, so use it only for text word search. To search in title only, type [ti] following each word.! e.g.! aort*[ti] AND ruptur*[ti]



Tips-Pubmed

To combine results (set numbers), click Advanced Search to see set numbers.

Results are in reverse chronologic order -- latest search result at the top.

Set numbers may be missing. They appear in MeSH Database instead of PubMed.

Capitalize AND and OR, and include the pound symbol (#) with setnumber.

Valid clinical evidence: In addition to limits mentioned above under Search

Process,

For systematic reviews, combine final set AND systematic[sb].

Quick & dirty method: Use “Clinical Queries” option; type a simple query.



Tips-Pubmed

Links to full textGet It Drexel Fulltext links appear only if you use aPubMed link on a Library web page.

Get It links reveal Drexel online availability." “Limit tofull text” misses much Drexel full text.



Trouble-shooting

RESULTS TOO LARGE?

Was logic correct?

Search MESH Headings as Major topic (Focus).

Instead of text words (title, abstract, etc.), search only title words:

OVID: topic*.ti.!PubMed topic*[ti]

LIMIT to Review articles, recent years, etc.

Limit to Core Clinical Journals (OVID limit; PubMed Subset limit)

Select one or two subheadings, instead of all.

Don’t explode MeSH; just search the broad term.

Add another topic using AND.



Trouble-shooting

RESULTS TOO SMALL?

Was logic correct?

Can unnecessary topics be removed, leaving only the most critical ones?Use Scope Notes to find other MeSH Headings and synonyms for text wordsearch.

Display MeSH Headings of known, highly-relevant articles, and look for otherMeSH Headings that had not occurred to you. Add them to the search.

EXPLODE to include more specific MeSH headings

Search ALL Subheadings (don’t select any)

Don’t search MeSH as Major Topic (Focus)



Trouble-shooting

Search text words (title, abstract, etc.) in addition to MESH.

Instead of searching words in titles only, search title, abstract, etc..

Think of word variations when searching title/abstract words:

Synonyms:! vitamin C vs. ascorbic acid! kidney failure vs. renal failure

Different word endings using truncation character:

E.g.!diaphragm*! Retrieves diaphragm, diaphragmatic, diaphragms

Break up phrases (elder abuse vs. abus* and elder*)

Anticipate different spacings and British spellings. E.g. rollerblad* vs. roller blad*

! Esophag: vs. oesophag:

For drugs/chemicals, add Registry Number (substance name) to MESH and title/abstractwords.

Check for spelling errors



Examples

Boolean logic: Use () OR (() AND () OR)

Keywords From the literature

Ing01 Searching for Clinical Prediction Rules in MEDLINE (Pubmed)

Used most sensitive one

"predict$ OR clinical$ OR outcome$ OR risk$"

Example of using MeSH terms

"predict$ OR clinical$ OR outcome$ OR risk$" AND "Sepsis"

Yield: 70 articles (8 reviews)

(predict$[All Fields] AND clinical$[All Fields] AND outcome$[All Fields] AND("risk"[MeSH Terms] OR "risk"[All Fields])) AND ("Sepsis$"[All Fields] OR"sepsis"[MeSH Terms])

Yield: 28 more (2 more review)



Examples

Pubmed VS. MEDLINE

Won03 Developing Optimal Search Strategies for Detecting Sound ClinicalPrediction Studies in MEDLINE

Pubmed:

(Predict$ OR Validat$ OR Rule$ OR Predictive Value of Tests) AND("Sepsis$"[All Fields] OR "sepsis"[MeSH Terms])

Yield 2678 (241 review)

Ovid MEDLINE

(Predict$ OR Validat$ OR Rule$ OR Predictive Value of Tests) ANDsepsis

Yield 4433 results



Examples

Pubmed VS. MEDLINE

Won03 Developing Optimal Search Strategies for Detecting Sound Clinical PredictionStudies in MEDLINE (con’t)

Ovid MEDLINE

(Predict$ OR Validat$ OR Rule$ OR Predictive Value of Tests) AND *sepsis/

*<subject heading> command to focus a known subject heading

* search term / = MeSH (Major topic)

Yield 1410 results

(Predict$ OR Validat$ OR Rule$ OR Predictive Value of Tests).ti.sepsis.ti.

4 and 5

Yield 269



Examples

Pubmed website:

: Search by Clinical prediction guides (narrow)

(sepsis) AND (validation[tiab] OR validate[tiab])

432 (46 review)

Example

Hol05 Optimal search strategies for identifying sound clinical prediction studies inEMBASE.

Manually: valid$

OR$

index$

OR model/exp OR model(valid$OR$index$OR model/exp OR model) AND (sepsis/exp OR sepsis)

AND$'human'/de

7393 results…



Endnote

Manage bibliographies

Import Pubmed/Ovid MEDLINE resultImport/find full text PDF

Cite while you write (CWYW)

Real-time update latest publication

literature review for clinical prediction rules cgmh slides

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