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WHSL Clinical Questions using PubMed: More Examples Using Other EBM Resources

The first in a series of evidence-based medicine guides

Scenario 1

Your patient presents to the emergency department at a large city hospital with chest pains. You have heard that there is a new diagnostic test (Troponin I assay) which can be used to diagnose acute myocardial infarction within 3 hours after presentation, and you are eager to learn more  about the diagnostic accuracy of this test. Find a 2012 study on this topic.

Scenario 2

Data from Kwazulu Natal, South Africa, suggest that almost all patients with multi-drug-resistant (MDR) tuberculosis are HIV-positive, with a fatal outcome. Since, there is limited data for the treatment-related outcomes of MDR tuberculosis in settings with a high HIV prevalence, you are asked to find an article investigating the associations of these diseases in settings where patients do not have access to HAART to formulate recommendations for control programmes.

Using EE+ for Search 2

Different Resources

Take home message: You will get different results from different resources. Finding the evidence requires that you learn to search them all. Some resources will be better suited to research than clinical practice; and vice versa. Experience helps in deciding which resource to use, so the more you practise, the easier it becomes.


P - Myocardial infarction

I - Troponin I assay

C - None

O - Diagnostic accuracy

Search Strategy 1

  1. Use Clincial Queries in PubMed to find this article.
  2. Find MeSH terms for Myocardial infarction and Troponin I assay.
  3. Clinical Category: Diagnosis
  4. Scope: Narrow
Is it necessary to add "diagnostic accuracy" as your Outcome to this search in order to find this article?

Using Essential Evidence Plus for this Search

Different databases will use slightly different strategies. Try running the same search from PICO 1 in another database

See what happens when you search using Myocardial infarction AND Troponin I assay

Then refine your results by selecting the Diagnosis option on the left of the screen. 


P - South African patients with MDR Tuberculosis  

I - No access to HAART

C - None

O - Prognosis 

Search Strategy 2

  1. Use Clincial Queries in PubMed to find this article.
  2. Find MeSH term for Multi-Drug Resistant Tuberculosis
  3. Select Clinical Queries
  4. Add HAART AND South Africa (non-MeSH terms) to the search bar
  5. Clinical Category: Prognosis
  6. Scope: Narrow
  • What happens to your search if you use the MeSH term for HAART (Antiretroviral Therapy, Highly Active) instead of the textword (keyword)?
  • What happens to your results if you make your scope "Broad"?
  • What happens if you use the MeSH term "Extensively Drug-Resistant Tuberculosis" instead of the MeSH term for Multi-Drug Resistant Tuberculosis?
  • Why do you think you get different sets of results each time with each different search strategy?