Evidence-Based Medicine Step-By-Step

This worksheet will lead you through the basics of the evidence-based medicine (EBM) process. Start by developing your question. Next, explore EBM resources on the Web and in print that will help you answer your question efficiently.

Formulate the Question

First, your question a background or a foreground question? A background question might ask about general knowledge of a disease/disorder. Background questions usually ask who, what, where, how, or why about a disease, drug, or intervention. For example, is "how do SSRI's work to treat depression?" or "what are the risk factors for depression?"

"If your question is of a more general nature, use online textbooks like ACP Medicine, eMedicine (www.emedicine.com/) (free but registration required), UpToDate, print textbooks in the Health Sciences Library, or find review articles in Medline.

To answer the questions "how do SSRI's work to treat depression?" or "what are the risk factors for depression?" you could use either of two authoritative resources in the STAT!Ref online textbooks. One is  ACP Medicine, which has an informative overview article that discusses risk factors and the pathophysiology of depression, and the other is Goodman & Gilman's The Pharmacologic Basis of Therapeutics, which has an overview of the drug therapy of depression."

Or, is this a foreground question-asking for specific knowledge about management, diagnosis, etc. of a patient's disorder that requires knowledge of the latest research in the field? Foreground questions usually consist of four parts. For example, in patients with a history of postpartum/postnatal depression which antidepressant drugs are the most effective at preventing a recurrence of postpartum depression? Construct an answerable question using PICO:

1. Patient or problem

   _____________________________________________________________

2. Intervention, prognostic factor, or exposure

   _____________________________________________________________

3. Comparison

   _____________________________________________________________

4. Outcomes

   _____________________________________________________________

Write it out in the form of a question:

_____________________________________________________________

Find the Evidence

Once you have developed your question, start searching the literature.

Some resources offer evidence-based summaries of the primary evidence. You use these when you don't have time to find original research articles, read each article, and do in-depth critical appraisal as you learned in Medical Decision Making and Pharmacology. Good places to look:

• Practice Guidelines (guideline.gov)
• The Health Sciences Library's EBM Reviews databases (full text articles included!) This link allows you to search all three at once. Or search them individually:
  • EBM Reviews: Cochrane Database of Systematic Reviews (Topic Reviews)
  • EBM Reviews: Database of Abstracts of Reviews of Effects (Article Reviews)
  • EBM Reviews: ACP Journal Club (Article Reviews)
• Evidence-Based On-Call (www.eboncall.org) This database is designed for hospital clinicians who want to integrate the best available evidence with their own personal skills and expertise to improve the care of their patients. In this evidence compendium, you will find evidence-based summaries of 38 on-call medical conditions such as atrial fibrillation or deep venous thrombosis. Every recommendation that is included links to a one-page summary (called CATs) of every article included.
• Bandolier Evidence-Based Health Care (www.jr2.ox.ac.uk/bandolier/index.html) This free Internet journal provides advice about particular treatments or diseases for healthcare professionals and consumers using evidence-based medicine techniques.
• SUMsearch (sumsearch.uthscsa.edu) SUMSearch selects the best resources for your question, formats your question for each resource, and makes additional searches based on results.
• TRIP Database (www.tripdatabase.com) Searches for evidence-based websites, practice guidelines, query answering services, e-textbooks, and more.

If you don't find an evidence-based summary of the primary evidence, then go out and find the original studies:

• Medline - try limiting your search to specific study types such as randomized controlled trials or to articles that have an evidence-based review.
• EBM Reviews: Cochrane Central Register of Controlled Trials - includes abstracts and citations for controlled trials.
• The Users' Guides to the Medical Literature (www.cche.net/usersguides/main.asp) will assist you with primary literature evaluation and critical appraisal. You will find guides on how to read most every type of study.

Answering our example question

So, back to our example about drug therapy of postpartum depression. Here's an example of a Cochrane review article on the topic.

Need assistance answering your clinical question? Ask your Health Sciences Librarian by phone at the Reference Desk (816) 235-1885 or via e-mail.