1. Searching EMBASE Alex Denby Regional MI Manager
London Medicines Information Service
(Northwick Park Hospital)
Continue with searching but this time look at Embase which is also accessible via NLH NHS.
Not available on PubMed (which is just a public version of medline).
Ovid has Embase & EMTREE scope notes.

2. Session aims
To understand the concepts of a basic search strategy in Embase
To describe the EMTREE thesaurus in detail so that you will be able to apply EMTREE to use Embase efficiently
To carry out advanced Embase searches

3. Plan What is Embase? (precourse material)
Medline v Embase (precourse material)
EMTREE
NLH Software – searching tools
Worked Examples

4. Searching EMBASE Controlled vocabulary = EMTREE Uses natural language
This database also has a controlled vocabulary which can only be used with EMBASE = EMTREE.
This is different to MeSH therefore you can’t always use the same search term you have found worked in Medline to search in Embase.
Emtree terms use more natural language than MeSH and is more intuitive. Eg. e.g. chronic fatigue syndrome [EMBASE] v fatigue syndrome, chronic [Medline]; Lung cancer [Embase] vs. Neoplasm [Medline].
USA spelling e.g. estrogen rather than oestrogen but will still recognise English spelling when searching for a term.
Terms are usually singular – foot not feet (will still map you if you use feet)
Noun rather than adjectival form – heart disease rather than cardiac disease
Acronyms & abbreviations are recognised.
INNs used where possible for drug names.
Again these terms are assigned by the indexers to make searching more relevant & precise.
EMTREE is arranged as a hierarchy and consists of over 45,000 descriptors and over 190,000 synonyms.
Compared with ~18,000 terms in Medline.
EMTREE is also divided into facets – 15
Thesaurus updated annually – rarely any need to add terms in between times. At the yearly reload terms may be added, removed or to change format – the database automatically updates the terms previously applied. If a term is changed the old term becomes a synonym for the new term.
>40,000 preferred terms => subject terms describing scope of article
>175,000 synonyms => alternate subject terms used as pointers to preferred terms eg trade names, chemical names, street names, common names etc.
Indexers assign terms to describe the content of the article
Often a record will have many terms – some as many as 40 or 50 – c.f. Medline which has average 20
(a search I was doing identified an article about Psychotropic Drugs in Pregnancy and Lactation in the Journal of Psychiatric Practice 2005 and this had 151 terms!!!)
and up to 30 drug names can be indexed (differs to MeSH). If there are more than 30 drug names then the term ‘unindexed drug name’ is used.
Explode & major still apply in advanced searches. Same concept as in Medline.
Hierarchical structure allows this.
Controlled vocabulary = EMTREE
Uses natural language
US spellings rather than British
INNs used where possible
Acronyms & abbreviations can be used
Tree Structure – Hierarchy
Indexing: Terms added/Drug names

5. NLH Software
Open Internet and type:
Select ‘Specialist resources’ / ‘Search Specialist Databases’
Enter Athens password
Click on “Healthcare Database Advanced Search” and select Embase
EMTREE isn’t held on a separate website like MeSH, so the only places you access the EMTREE is via the software interfaces you use – we will be using NLH again for the purposes of demonstration
If you have questions about other software feel free to ask during the workshop

6. NLH Software Embase 1974 to date 2 options to search for terms:
Thesaurus mapping
Browse headings
Just like Medline previously, avoid searching across all the databases using a free text search and as we have discussed this is not the best way to search these databases
Embase 1980 to date – NB The date is incorrect, Embase actually goes back to Note again that there is no smaller breakdown of the database like there used to be in Dialog
The 2 search functions work in the same way as searching Medline
Eg: SSRI (tick map to thesaurus)
Map to Serotonin Reuptake Inhibitor – NB no scope note etc but these should be available after the next reload (late 2009)
As EMTREE only available via software have to rely on scope notes given by the software interface – not v good in NLH – but as we said earlier EMTREE is much more common English and easy to understand much more likely that what we mean and what they mean are the same thing unlike MeSH
OR use browse feature: (this has not been working recently)
Facet D: Chemical and Drugs – Central Nervous System Agents – Psychotropic Agent – Psychostimulant Agent – Antidepressant Agent – Serotonin Uptake Inhibitor -

8. Explode/Major descriptor
Includes everything below in the tree structure.
‘exp’ is put before keyword in results
Major description (Focus)
Only includes articles where the MeSH heading (descriptor) is the main focus of the article
‘’ is put before keyword in results
Explode & major still apply in searches. Same concept as in Medline.
Hierarchical structure allows this.
Explode: e.g. SSRIs. You will get all the hits on the term below it in the tree – this does include new drugs such as escitalopram. Also recognises SNRIs as a separate group and has these terms listed underneath.
Major (NLH) / Focus (OVID): as for Medline: Tick the Focus or Major descriptor box to focus your search and remove articles where the Emtree term is not considered to be the main concept.
Select: does not explode or focus but selects the keyword with all the subheadings.

10. Subheadings
Many more subheading options for drugs compared with Medline
e.g. diclofenac
By choosing ‘Select’, all subheadings for the term will be chosen without either Exploding or Majoring on the term.
EMTREE Links or Subheadings are divided into 2 types:
Drugs links & Disease links – you will be offered a different list depending on whether you are searching a drug or a disease as a term
Drug therapy appears in both medical & drug links.
NB Links/subheadings were added in 1988 and can only be searched from that year onwards.
Example: Thesaurus map diclofenac
Select diclofenac & subheadings – show that many more options compared with options in MeSH. Show subheadings – esp drug combination, drug comparison, different types of drug administration, pharmacoeconomics etc.

12. CAS numbers No real need to use them in EMBASE
Most medicines have EMTREE terms – even recently licensed ones
If a drug hasn’t got an EMTREE term assigned – use free text
No need to use this as most drugs are EMTREE terms – show that there aren’t the same problems with drugs like venlafaxine, olanzapine, rabeprazole etc.. as there are in Medline.
Even newly licensed drugs such as duloxetine have been assigned terms already. Rasagiline which has been granted a licence but is not yet launched (as at June 05) has had an EMTREE term since Feb 97!
If time, ask the audience to come up with a new drug or a drug in development and check to see if it has an EMTREE term. E.g. certolizumab, tocilizumab, ulipristal,
Get people to think of drugs in the pipeline, newly launched drugs -ask them to see if EMTREE terms exist
e. Agomelatine (launched for depression), ustekinumab (launched for psoriasis), tolvaptan (hyponatraemia), ulipristal (emergency contraception), denosumab (osteoporosis), mepolizumab (hypereosinolic syndromes), golimumab (RA/AK/PsA) – all map to thesaurus even though some are not yet launched/PIII trials,
Date added is important for newer drugs as they may have only been added as an EMTREE subject heading recently – may need to do a free text search as well to include articles prior to this date
Free Text searches can be used for terms that don’t have a EMTREE heading yet, in Medline this applies to a lot of drugs but with Embase as it is more drug focused most drugs will already have an EMTREE heading even really new drugs – see examples above
If doing a free text search use ‘any field’ from the drop down menu

13. Limits Limit searches in similar way to Medline
Differences compared with Medline
Show limits & the differences compared with Medline
The limits are set up in the same way at the bottom of the search page but the although the main headings are the same there are some difference between what you are offered in Embase and Medline
In Embase:
Publication type – fewer options than Medline but see next slide - Article, Book, Book Series, Conference Paper, Editorial, Erratum, Journal, Letter, Note, Proceeding, Report, Review, Short Survey
Age Groups – slightly different ones offered and definitions –
Human Age Groups Embryo (first trimester), Infant (to one year), Child (unspecified age), Preschool Child (1 to 6 years), School Child (7 to 12 years), Adolescent (13 to 17 years), Adult (18 to 64 years), Aged (65+ years),
Embase: infant (to one year), Medline: all infant (to 23 months); Embase preschool (1-6 years), Medline preschool (2-5 years), etc.
Other – route of administration

14. Publication types
Publication types have their own facet / tree top of EMTREE terms that are searchable
Facet J: types of article or study
Build up your search and combine in the usual way (using BOOLEAN) with other search terms
Show by clicking on browse headings – show facet J, click on types of study, click on controlled study, then show randomized controlled trial.
So in Embase rather than limiting to a particular type of study like you would do in Medline you can search for the term via mapping and combine as you would other searches
Medline also has publication types as a tree heading but probably easier to use as a limit function

16. Worked example 1
Are there any papers specifically about the use of linezolid for the treatment of MRSA?
(Workshop question 1)
Linezolid is an EMTREE term – it is not a MeSH term
Select drug therapy
MRSA maps to methicillin resistant Staph aureus as a keyword.
Select major descriptor.
Combine the two terms, then limit them to human and English

17. .

18. Worked example 2
Are there any review articles about inhaler use in asthmatic children under 4?
(Workshop question 2)
Inhaler maps in the Emtree to inhaler, metered dose inhaler and powder inhaler. Explode the term inhaler, to see that this include MDI and powder inhalers.
Asthma is a keyword, explode the term to include all the types of asthma, such as exercise induced, allergic and mild intermittant asthma.
Combine the two terms.
Then limit the search:
Publication type – review
Age: infant to 1 year, child 1-6 years
Human
English language

20. Worked example 3
Is there any evidence that minocycline is more effective than any of the other tetracyclines that are licensed for the treatment of acne (tetracycline, lymecycline, oxytetracycline, doxycycline)?
(Workshop question 5)
We want to search for minocycline, other tetracyclines and acne.
Can use the subheading ‘drug comparison’
Search for minocycline – subheading drug comparison
Search for tetracycline – expand the tree under tetracycline derivative to select the relevant ones
Explode the term for Acne to include all sub-tree keywords
Combine the 3 searches with AND.
Can limit to human and English.

22. Any questions?