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Evidence Based Practice

This tutorial was developed by staff at Duke University Medical Center Library and the Health Sciences Library at the University of North Carolina at Chapel Hill. It is used with permission by Saint Louis University Medical Center Library.

The Literature Search

Acquiring the Evidence


the evidence
3. Select the appropriate resource(s) and conduct a search


In the previous section, we learned how to construct a well-built clinical question. Using that question, we will move on to the literature search.


For our patient, the clinical question is:

In patients with type 2 diabetes and obesity, is bariatric surgery more effective than standard medical therapy at increasing the probability of remission of diabetes? It is a therapy question and the best evidence would be a randomized controlled trial (RCT). If we found numerous RCTs, then we might want to look for a systematic review.



Constructing a well-built clinical question can lead directly to a well-built search strategy. Note that you may not use all the information in PICO or well-built clinical question in your MEDLINE strategy. In the following example we did not use the term “male.”  You don't need to search all elements.



Clinical Question

MeSH term

Patient / Problem obese, diabetes type 2, male

Diabetes Mellitus, Type 2


Intervention stomach stapling (gastric bypass surgery; bariatric surgery) bariatric surgery
Comparison (if any) standard medical care  
Outcome remission of diabetes; weight loss; mortality  
Type of Question therapy (see below)
Type of Study RCT Clinical Queries – Therapy/narrow
Limit to randomized controlled trial 


Possible strategy: 

(("Bariatric Surgery"[Major]) AND "Diabetes Mellitus, Type 2"[Major]) AND "Obesity"[Major]  Filter to Randomized Control Trials