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? Medline v Embase EMTREE
NLH Software – searching tools
Worked Examples

4. What is EMBASE? Major biomedical & pharmaceutical database
European focus
>3,500 journals, 70 countries
Subject coverage focuses on human medicine
Includes drug research, pharmacology, pharmaceutics, health policy and management, public health
Provides current and comprehensive information on drugs and pharmacology, and all other aspects of human medicine and related disciplines.
EMBASE covers literature from all over the world but concentrates in particular on European sources. The emphasis of the database is on the pharmacological effects of drugs and chemicals.
Over 5000 journals from over 70 countries are scanned.
Approximately 375,000 entries are added yearly.
~80% of records have an abstract and over 40% of the current data is drug related.
Records date back to 1974.
Areas of coverage are drug research, pharmacology, pharmaceutics, toxicology, clinical and experimental human medicine, health policy and management, public health, occupational health, environmental health, drug dependence and abuse, psychiatry, forensic medicine, and biomedical engineering/instrumentation. There is selective coverage for nursing, dentistry, veterinary medicine, psychology, and alternative medicine. .
EMBASE articles are indexed within 15 days of receipt and are online very soon after that. An online thesaurus for the EMTREE classification system is available in each of the EMBASE files.
EMBASE belongs to a family that consists of 3 separate databases.
Drugs & Pharmacology (EMDP) and Psychiatry (EMPS) are considered as sub sets of EMBASE hence this session will concentrate on EMBASE

5. 30% overlap between the Medline and Embase
EMBASE vs. Medline
EMBASE
European coverage
1974 onwards
Drug/pharmacology focus
Updated faster
EMTREE indexing
MEDLINE
USA coverage
1950 onwards
Wide medical coverage
In process
MeSH indexing
When we compare EMBASE & Medline.
Coverage of Embase:
40% - drug research, pharmacology, pharmaceutics, pharmacy and toxicology
40% - human medicine (clinical & experimental)
Basic biological research relevant to human medicine
Health policy, management & pharmacoeconomics
Public, occupational & environmental health etc..
Also: nursing, dentistry, veterinary science, psychology
Indexing and limit functions are more intuitive and comprehensive, e.g. limit to a specific route of drug administration.
30% overlap with Medline
EMBASE indexes more drug related literature
EMBASE covers more European & Far Eastern journals
Medline covers more US journals
EMBASE is updated faster – average = working days for full article to appear c.f. 6-8 weeks for Medline (30% within 30 days , 60% within 60 days)
Overlap between Medline & Embase = ~30% therefore always search both
Many NHS sites can access Embase for free, but if not, it is expensive to buy.
Embase does not include papers before 1974, whereas Medline goes back to 1951.
30% overlap between the Medline and Embase

6. 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

7. NLH Software Open Internet and type:
Click “Login now” (LHS of screen)
Right click & then click on “create a shortcut”
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

8. 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
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 -

10. Explode/Focus Explode Focus (Major)
Includes everything below in the tree structure
Focus (Major)
Only includes articles where the MeSH heading (descriptor) is the main focus of the article
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 inclue new drugs such as escitalopram. Also recognises SNRIs as a separate group and has these terms listed underneath.
Focus (OVID) / Major (NLH): 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.

12. Subheadings
Many more subheading options for drugs compared with Medline
e.g. diclofenac
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.

14. 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.
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

15. 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),
Other – route of administration

16. 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

18. Worked example 1
Are there any papers about UK SSRIs or SNRIs being used in the treatment of Huntington disease?
NB SSRIs (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline), SNRIs (duloxetine, venlafaxine)
In Embase you will see that all of the drugs have EMTREE headings compared to Medline where we had to do free text searches for some of the newer agents
SNRIs are also recognised as EMTREE headings
Means you can do the search in one go by selecting all the drugs you are interested in and clicking search – combines all the terms with an OR
Alternatively you can explode the SSRI heading and then re do the search and explode the SNRI heading – this would mean you get a lot more hits back than maybe you needed – depends on the question being asked if you were looking at the group generally as opposed to just UK licensed then exploding the term may be more appropriate

20. Huntingtons disease is mapped to the thesaurus term Huntingtons chorea.
Previously in the scope note you would be told what else this term was used for – but this has now been removed.
You can see this term has been in use in Embase since 1979.
Use ‘select’ in order to include all the subheadings

21. Searches can be saved and easily retrieved again.
Searched SSRI, exploded the term and selected the SSRIs available in the UK.
Did the same for SNRI
Combined the two searches with OR, to include all of the articles.
Searched for Huntingtons disease, which was mapped to Huntingtons Chorea.
Combined with the drugs, using AND, to find those articles containing both search terms.
Always a good idea to save the search. It can be retrieved by going to ‘my saved searches’
Searches can be saved and easily retrieved again.

22. Worked example 2
Are there any articles which discuss using high dose vitamin supplementation to treat autism ?
Autism is an EMTREE term
NB This time there are other conditions under the term – depending on your enquiry you may want to explode and include all these terms or just search the term itself
Orthomolecular Therapy (the MeSH term we used) is not an EMTREE term
Try other suggestions – remind group that EMTREE thinks more in natural language.
Type vitamins  maps to “vitamin” (as plurals not used) – show tree below it and choose explode
Type high dose  maps to “drug megadose” (NB no similar option in Medline)

26. Searched for autism, which is a thesaurus term.
Chose ‘select’ and ‘explode’ for autism to include all the subheadings and associated terms.
Searched vitamin, and exploded to include all associated terms.
Searched high dose – mapped to drug megadose
Combined all three terms.
Limit to human and english

27. Any questions?