For our patient, the clinical question is:

In elderly patients with congestive heart failure, is digoxin effective in reducing the need for rehospitalization?

It is a therapy question and the best evidence would be a randomized controlled clinical trial.

Patient Population	congestive heart failure, elderly	heart failure, congestive Limit to Aged
Intervention	digoxin	digoxin
Comparison (if any)	none or placebo
Outcome	rate of hospitalization	hospitalization
Type of Question	therapy
Type of Study	RCT	Limit to randomized controlled trial as publication type

Constructing a well-built clinical question can lead directly to a well-built search strategy. Note that you may not use all the pieces of the well-built clinical question in your MEDLINE strategy. In the following example we did not use the term "elderly." We also did not include the word therapy. Instead we used the publication type, RCT, to get at the concept of treatment. However, you may consider the issue of age later when you review the articles for applicability to your patient.

Select a resource

The practice of Evidence-based Medicine advocates that clinicians search the published literature to find answers to their clinical questions. There are literally millions of published reports, journal articles, correspondence and studies available to clinicians. Choosing the best resource to search is an important decision. Large databases such as MEDLINE will give you access to the primary literature. Secondary resources such as ACP Journal Club, POEMS, Clinical Inquiries, and Clinical Evidence, will provide you with an assessment of the original study. The Cochrane Library provides access to systematic reviews which help summarize the results from a number of studies.

Detailed list of resources for practicing EBM

For this question, we have chosen MEDLINE as our resource. MEDLINE is the most comprehensive resource for health-related literature searches and is accessible to everyone through PubMed. We are going to show two sample literature searches:

1. Using PubMed from the National Library of Medicine (see below)

2. Using MEDLINE from Ovid Technologies, Inc. (Click here to see the search example). When you are finished with the Ovid search, click the close box in your browser's window to return to this unit.

Formulate the strategy

The following example search was conducted in December, 2003.

Step 1: Search each important concept separately.

Enter the term for Pauline's condition: congestive heart failure. PubMed attempts to map your term to an appropriate Medical Subject Heading (MeSH). Click on Details to see what terms PubMed used in its search. You want to be sure it found the appropriate MeSH Terms and Text Words.

Next, Clear the search box and enter the term for the intervention, digoxin. Again, PubMed attempts to map your term to an appropriate Medical Subject Heading (MeSH). Click on Details to see what terms PubMed used in its search. You want to be sure it found the appropriate MeSH Terms and Text Words.

Next, Clear the search box and enter the term for the outcome, hospitalization. Again, PubMed attempts to map your term to an appropriate Medical Subject Heading (MeSH). Click on Details to see what terms PubMed used in its search. You want to be sure it found the appropriate MeSH Terms and Text Words.

Step 2: Combine the separate sets of articles.

Click on History to view the 3 separate sets of articles you retrieved. You need to combine them to identify those articles that contain all 3 terms. In PubMed you must use the "#".

Step 3: Limit the results to the appropriate publication type, language and human.

This is a therapy question. We know from the previous discussion that the best evidence for a therapy question is a randomized controlled clinical trial (RCT). Use the Limit function to limit the results to randomized controlled trial as a publication type. At this point we can also limit to English language, human, and age group, if needed.

Review the results

Review the titles and abstracts to identify potentially relevant articles.  While article #17 seems more appropriate for information about hospitalization, we chose #18 because it is the original DIG Study.

Supplement: Additional EBM Strategies for Searching MEDLINE