Chapter 7 Evidence-Based Medicine
INTRODUCTION TO EVIDENCE-BASED MEDICINE (EBM)
What Do I Need to Know to Use EBM?
Using EBM requires that you understand the basic principles of epidemiology and biostatistics. In addition, you should have a working knowledge of the medical literature, including common study designs, and feel comfortable performing a basic MEDLINE search. Brief reviews are in the reference list (Gehlbach, 2002; Greenhalgh, 2006).
What Does “Evidence-Based Medicine” Mean?
EBM is the “conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients” (Sackett et al., 1996). EBM assumes that physicians whose practice is based on a solid understanding of the underlying evidence will provide superior patient care. EBM guides are available for interpreting most types of articles found in the medical literature. This chapter only discusses EBM for treatment questions, because these are most commonly encountered during the clerkship. Refer to the original JAMA series (Oxman et al., 1993) or review texts (Straus et al., 2005; Greenhalgh, 2006) for additional EBM topics.
How Does EBM Relate to My Other Studies?
You will use EBM to assist with management of a specific patient or problem. The general learning during the clerkship will still come from participating directly in patient care, from reading textbooks or quality review articles, or from online resources such as the Computer-assisted Learning in Pediatrics Project (CLIPP) (http://clippcases.org).
How Do I Use MEDLINE?
Students commonly find too many or too few articles or find articles that are not relevant. Review the basics of MEDLINE searching (Greenhalgh 1997; Greenhalgh 2006) and ask for help from a medical librarian. The following suggestions will improve your search strategy:
1 Be sure that you understand the concepts of MeSH headings and Boolean operators (“and,” “or,” and “not”).
2 Use the PICO format to focus the question and define search parameters.
3 Use the “age-limit” function appropriate to your patient.
4 Use “quality filters” to limit your search. To identify treatment articles, add “randomized controlled trial,” “clinical trial,” “meta-analysis,” and “practice guideline” to the search strategy, or use the EBM functions of Ovid and PubMed. Ask your librarian for help.
5 Read the abstracts identified by your search and choose one to three of the best articles that are relevant to your patient. Next, read each article to gain an understanding of the study’s hypothesis, methodology, and conclusions. Then, “map out” each study on paper to make the methodology and its strengths and limitations clear. This will help you determine the validity and significance of the results (Gehlbach, 2002; Greenhalgh, 2006).
