EBM
Contents
Evidence-Based Medicine -- EBM
EBM Definition
Evidence-Based Practice Guidelines and EBM
History
Epistemology of EBM
Evidenced Based Medicine (EBM) includes the use of the published, medical literature to guide medical practice. Inherent in this, is the ability to judge the quality of the medical literature, to understand what statements can rationally be made from the medical literature, to appreciate the strength of those inferences, and to realistically apply them to a particular patient or clinical situation.
The EBM Process can be summarized by four steps: (1) Formulate a sensible, focused clinical question. (2) Search the medical literature for evidence related to the focused, clinical question. (3) Rate the quality of the available studies. (4) Apply the evidence to a particular patient or clinical situation.
In the first step, the clinician must decide explicitly what patient population he or she is interested in, what tests, treatments, and alternatives he or she is considering, what the outcome of interest is (and how is it to be measured). These questions can be remembered with the mnemonic "PICO": Patient, Intervention(s),Comparisons, and Outcomes.
The second step of the EBM process is to search the medical literature. Aside from understanding the methods, strengths, and weaknesses of various search strategies and search engines, this step also involves looking for the highest level of evidence. In general, Systematic Reviews (not to be confused with general Review Articles) are considered the highest level of evidence, followed by Randomized Controlled Trials (RCT), then Case-Control Studies, followed by Expert Opinion and then, lastly, anecdotal evidence.
The third step--rating the quality of the available studies--involves a knowledge of research methodology that is important to make valid conclusions. For example (for RCTs): Was a control group used? Was assignment to an experimental vs. control group truly random? Were patients, treatment providers, and outcome assessors blinded to group assignment? What is the risk of a Type I or Type II error? What is the effect size? Or for Systematic Reviews: Was the literature review truly comprehensive (and how can you know)? Was the assessment of study quality rigorous and subjectively graded? Can numerical assessments be statistically combined (a "meta-analysis") to increase statistical power? The answer to these questions often depends on the particular parameters decided in the first step.
The last step of the EBM process is the ability to translate the ideal findings of carefully controlled studies to the less-ideal and less-carefully-controlled situation of a particular patient. What are the particular risks and benefits for this patient? What are his or her preferences? What are the costs, alternatives, and availability of particular treatments? Even for a statistically significant finding, is the effect size practically significant? Does the practitioner have the necessary skill or resources to deliver a treatment or to monitor the outcomes?
As medicine has continued to grow and become more complicated, the number of medical specialties has increased and their depth matures. At the same time, the amount and complexity of the medical literature has similarly grown. In this sense, Evidenced Based Medicine can be considered a burgeoning medical specialty, with the medical literature itself as the object of study.
Reference: Guyatt, G., Rennie, D. (eds.) Users' Guides to the Medical Literature: Essentials of Evidence-Based Practice. Chicago. American Mecial Association. 2002.
Advantages
Limitations
HIT’s Role in EBM
The link below describes a process for building health science knowledgebases used by evidence-based decision support tools. This gives an expanded view of the processes corresponding to the quality metrics, practice guidelines, knowledge services and tools, and CQI feedback loops.
