Medline v Embase by Lucy Anderson

I recently heard someone say ‘…so if Medline is in Embase then why search, Medline?’ Apart from the fact that I love MeSH (Medical Subject Heading) I couldn’t give them a good explanation! So I decided, like a good librarian, to look it up. Here is a selection of what I found.

PubMed (Medline) came third and Embase fourth in a piece of research looking into the best place to find RCTs (Randomised Controlled Trials) of physical therapy interventions (Michaleff et al., 2011). CENTRAL (available at www.thecochranelibrary.com ) was the best place to find them, with Pedro (a physiotherapy database available at http://www.pedro.org.au/ ) coming in second.

McGill University Health Centre have produced a very informative Embase V Medline factsheet (McGill University Health Centre Libraries, 2013) which highlighted, to me, that Emtree is updated 3 times a year, MeSH is updated annually, and there are more thesaurus terms in Emtree than MeSH.

The North West Medicines Information Centre has a presentation that is available online called ‘searching Embase’ In the presentation there is a slide titled ‘why you still need Medline’ it explains the indexing methods differ between the databases, there are more subheadings in Medline and the fields and limits are different in each database. Obviously this was part of a training session; it would be useful to know Pharmacists’ views following the session.

Elsevier, the publishers of Embase, have a useful document called ‘What are the differences between Emtree and MeSH?’ (Elsevier, 2012) It is no surprise the document favours Emtree, but it does state that the history feature of MeSH maybe useful to some people. It gives the results of a study comparing Emtree and MeSH when searching for new drugs. It concludes that Embase retrieves more results than Medline when searching for new drugs.

Another Elsevier document gives information about the mapping of MeSH subheadings to Embase terms/subheadings and the mapping of publication types (Crowlesmith, 2011).

If you are searching for ‘adverse effects’ in the 2 databases then a more sensitive search can be ‘constructed with greater ease in Embase than in Medline’ (Golder & Loke, 2012b) but “adverse effects filters should be applied with caution in Embase” (Golder & Loke, 2012a). This would be a great discussion at a Clinical Librarians meeting and would help me understand the research, as I am not sure I do at the moment!

A discussion at the LIHNN Big Day Out in March concluded that when in doubt search both Embase and Medline. I am sure there is more information available about the differences and it would be great to hear people’s views on ‘Medline V Embase’.

References

Crowlesmith, I., 2011. Coverage of Medline in Embase, Available at: http://www.elsevier.com/__data/assets/pdf_file/0017/127331/Coverage-of-Medline-in-Embase.pdf [Accessed May 14, 2014].

Elsevier, 2012. What are the differences between Emtree and MeSH?, Available at: http://www.elsevier.com/__data/assets/pdf_file/0019/127333/Embase_Emtree-and-Mesh-Whitepaper.pdf [Accessed May 14, 2014].

Golder, S. & Loke, Y.K., 2012a. Sensitivity and precision of adverse effects search filters in MEDLINE and EMBASE: a case study of fractures with thiazolidinediones. Health information and libraries journal, 29(1), pp.28–38. Available at: http://www.ncbi.nlm.nih.gov/pubmed/22335287 [Accessed May 14, 2014].

Golder, S. & Loke, Y.K., 2012b. The performance of adverse effects search filters in MEDLINE and EMBASE. Health information and libraries journal, 29(2), pp.141–51. Available at: http://www.ncbi.nlm.nih.gov/pubmed/22630362 [Accessed May 14, 2014].

McEntee, J., Searching Embase. Available at: http://www.ukmi.nhs.uk/filestore/ukmiamt/EMBASEsearchingNationalCourseSep2013.pdf [Accessed May 14, 2014].

McGill University Health Centre Libraries, 2013. Medline v Embase. Available at: http://www.muhclibraries.ca/files/2013/10/embase-vs-medline_EN-FINAL.pdf [Accessed May 14, 2014].

Michaleff, Z.A. et al., 2011. CENTRAL, PEDro, PubMed, and EMBASE are the most comprehensive databases indexing randomized controlled trials of physical therapy interventions. Physical therapy, 91(2), pp.190–7. Available at: http://ptjournal.apta.org/content/91/2/190.long [Accessed May 14, 2014].

Lucy Anderson BA (Hons) MCLIP
Knowledge Specialist: Outreach and Liaison
Pennine Care NHS Foundation Trust

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2 Responses to Medline v Embase by Lucy Anderson

  1. shannon says:

    I guess it depends on why you’re searching. I mostly do systematic reviews and it’s pretty much required to search both though I’m not entirely convinced about the necessity, but old habits die hard in academia and peer-reviewed publishing. While Embase does state they include the full Medline database one of the problems with Embase is overzealous indexing so you get an atrocious amount of false hits versus the more selective indexing done by Medline.

    There are some papers out there discussing the overlap by using case studies to see which databases the included studies ultimately came from. Andrew Booth has also talked about this in regards to systematic reviews as to how much effort should be put into the databases considering the overlap (not sure if his paper on this was ever published).

    It would be great if we could convince those doing systematic reviews that it’s no longer necessary to spend so much time constructing and translating searches for use across databases when the returns are so low for so much effort.

  2. Tom Roper says:

    Yes, the EMBASE indexers’ liberal approach to subject indexing isn’t helpful when your aim is precision. To some extent this can be overcome by majoring. Nevertheless, there are some strengths that shouldn’t be ignored. For me these are:
    speedier indexing of new material than Medline, sometimes
    better coverage of the European literature
    better coverage of pharmaceutical literature
    While Emtree has its faults, I must say I do find some of its features better than MeSH, for example the drug administration subheadings, all 47 of them. It’s hard not to like a system that allows you to specify intratympanic drug administration, for example.
    Michaleff’s findings are explained by the fact that CENTRAL includes all MEDLINE human studies indexed as RCTs or Controlled Clinical Trials. Michaleff doesn’t mention this, so may be unaware of it. Apropos, there’s an interesting opportunity for people to get involved in screening EMBASE records for CENTRAL See http://www.cochrane.org/news/tags/authors/become-embase-screener-cochranes-innovative-embase-project-now-open and http://www.metaxis.com/embase/login.php

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