LibGuides: Evidence-Based Medicine (EBM): EBM as Process

EBM Practice

EBM begins and ends with the patient. The clinician sees a patient and an issue arises that represents a knowledge gap or question for the practitioner. A clinical question drives the rest of the process to acquire evidence that addresses the issue and provides recommendations for decision making.

Not all evidence is created equal. There are various frameworks for evidence rigor, but generally the strongest evidence is derived from multiple, well conducted randomized clinical trials. The level of evidence is dictated by both the type of study and the quality of the study or studies. Evidence from a single large, well-conducted RCT is considered better evidence than evidence from a rigorous case-control or cohort study. Expert opinion is considered to be the lowest level of evidence.Systematic reviews and meta-analyses provide recommendations from a cohort of studies that meet specific criteria.

Study populations should represent the same demographic as the patient, with similar health status.

Steps in EBM

ASSESS - Identify the patient problem or issue - what do you need to know?

ASK - Develop and answerable clinical question; use the PICO format to help create the question:

P - Patient
I - Intervention
C - Comparison
O - Outcome

ACQUIRE - Use the PICO elements to inform a search stategy;

APPRAISE - What evidence was found? Are the results valid? What is the strength of the evidence? Are results applicable to this patient in this situation?

APPLY - Apply the evidence and share what you found with the patient.

EBM Primers from UMASS Lamar Soutter Library

The primers were developed by the Lamar Soutter LIbrary at the UMASS Medical School and provide quick reviews of EBM processes and appraisal.

Introduction to the Evidence-Base
Provides an introduction to the Evidence-Base including the literature and resources,
Diagnosis Primer
To learn about the reliability of any diagnosis you make, it is essential to know the sensitivity and the specificity of a diagnostic test. You can find sensitivity and specificity data in studies that look at a diagnostic test in a patient group and how those outcomes compare to other available tests.
Therapy Primer
Knowing the evidence behind a therapy prior to recommending it is a vital skill that you will (and should) use again and again as a clinician. Understanding concepts such as absolute risk, absolute risk reduction, relative risk and number needed to treat are the tools you will use to understand good evidence in therapeutics.
Etiology and Prognosis Primer
Pprospective and retrospective studies work well for etiological and prognostic clinical studies. They may have more variables and thus more bias than would an RCT but they are excellent at following a group of people forward or backwards in time. The clinical studies that best demonstrate prospective and retrospective investigation are the cohort study and the case-control study
Harm Primer
Often, the Evidence-Based literature you find will discuss both and you will need to discuss with your patient the benefits of the therapy weighed against the risk of adverse effects. At other times, the information on harm is not that clear and the risk of a therapeutic intervention will not appear until the therapy is underway.
Bias Primer
If you know what types of bias are lurking in the literature, you will be able to better understand how they might affect the results of outcomes data you are reading. Then, you can use your skills as a manager of knowledge to compensate as best as you can.