Formulating Clinical Questions and Literature Searching

[box]This is a quick guide to searching for evidence for clinical questions which you may encounter.

For example you may be wondering whether diazepam is effective in the treatment of back pain.

The clinical question should be structured in the PICO format :

  Patient population or clinical problem  =   back pain

   Intervention(study factor/exposure)  = diazepam

C  Comparator (control ) =   placebo

O  Outcome factor           =   pain

Your search terms would be the bold terms, although you could add other search terms if you were comparing other interventions eg. Paracetamol/codeine etc.

Databases and methods

All the following databases available through CIAP :

1) Cochrane database (under evidence-based practice tab in CIAP)– for systematic reviews

a) on the opening page, click the tab Advanced search

b) enter search term back pain

c) enter search term diazepam

d) combine with AND

e) under restrict search by product – tick ‘systematic reviews’ limit


2) Medline database – usually choose 1948-present

a)click on Advanced  Search tab

b) enter back pain – will be mapped to Medical Subject Heading(MeSH) term

c)Tick explode box to widen search, then continue

d) do not choose any subheadings, click continue

e) enter 2nd search term diazepam

f) click explode, continue, on the next page click continue

g)combine searches 1+2 by ticking boxes next to them and clicking AND

h) click on limits, then additional limits and select evidence based medicine reviews

i) click on search

Useful articles and links

Haynes RB, Wilczynski NL. Optimal search strategies for retrieving scientifically strong studies of diagnosis from Medline : analytical survey. BMJ 2004 : 328 (7447) : 1040

Haynes RB. McKibbon KA. Optimal search strategies for retrieving scientifically strong studies of treatment from Medline : analytical survey. BMJ 2005 : 330 (7501) : 1179[/box]

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