Overview: Evidence-Based Medicine

Quality of resources for clinical decision-making in Evidence-Based Medicine is integral to identifying an outcome that will most likely yield positive results for patients.  Many steps, methods and considerations are integrated into medical practitioners' decision-making practice.

In the 1990s, the term, Evidence-Based Medicine was coined by D. M. Sackett as a useful method for systematically approaching the complexities of patient-care to identify and implement solutions aimed toward achieving best outcomes. Later, EBM was more broadly denoted as Evidence-Based Practice (EBP).

Definition: Evidence-Based Medicine

Evidence-Based Medicine (EBM) involves balancing best evidence + personal expertise and clinical reasoning skills + patient considerations. EBM involves the recognition that decisions made are not simply right vs. wrong, but rather best judgment.

A well-known quote about EBM is that it is, "the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients" (Sackett, 1997)

Evidence-based medicine involves combining the clinician's expertise with best available clinical research evidence (Sackett, et al., 1996)

EBM Considerations

1. Optimal clinical decision making requires awareness of the best available evidence
2. Use hierarchies of evidence for guidance in clinical decision making confidence
3. Evidence alone is never sufficient to make a clinical decision

EBM requires the nuanced, balanced consideration of three core components

1. Best evidence
2. Clinical expertise of the practitioner
3. Patient needs and preferences

The five steps of EBM are...

1. Ask and Assess
2. Acquire
3. Appraise
4. Apply
5. Assess

See below for details on each step.

The first EBM step involves Asking and Assessing

First, consider if your research or clinical question is a Background question of a Foreground question

Background questions

• Involve developing or refreshing general knowledge on a topic. They are focused on finding more information on a general topic. 
• Example: What are treatment methods for ischemia?

Foreground questions

• Involve identifying the best course of action for a patient.
• Example: Is it better to treat a 68-year old woman with chronic non-cancer pain with non-pharmacological interventions or opioids? 

Second, if foreground question, Assess patient's clinical needs. Then transform question into a clinical question using the PICO framework. PICO framework is used for foreground questions for clinical decision making.

PICO Framework

P = Population or Patient or Problem

I = Intervention

C = Comparison intervention

O = Outcome

Note: There are many clinical question frameworks. For example, you may also include S for Setting, T for Type of Study, or Type of Question.

The second step of EBM process is Acquire

You must identify the highest level of evidence available to answer your background or foreground question.

*It is important to consider if the type of clinical question is an etiology, prevention, diagnosis, prognosis, therapy, etc. question as this impacts the level of evidence you will find. (See EBM Pyramid below for levels of evidence quality. See chart below to match clinical question to evidence type.)

Evidence-Based Medicine Pyramid

EBM Pyramid and EBM Page Generator, Copyright 2006-2014 Trustees of Dartmouth College and Yale University. All Rights Reserved. Produced by Jan Glover, David Izzo, Karen Odato and Lei Wang.

About the EBM Pyramid

• A general heuristic to keep in mind is that the higher you go up the EBM pyramid, the higher quality the evidence.
• Because it takes more time, resources, expertise, etc. to conduct research that is higher up on the EBM pyramid, the less evidence is available in the resource type categories as you move up the EBM pyramid.

Note that the EBM pyramid is a flexible, general guide because you may not always be able to find the highest level of evidence on your research question. For example, the highest level of evidence of your research question may not be available, is poor quality, etc.

Match Research Questions to Research Methodology

Foreground questions require identification of the highest level of evidence based upon matching the clinical question type (etiology, prognosis, therapy) to the research method type. And see 'Match Research Question to Research Methodology' below.)

Foreground question resources should use of critically appraised evidence as much as possible. Ideally this involves systematic reviews, guidelines, etc. It can also include the use of critically appraised primary studies that address the clinical question when evidence synthesis are not available.

Match Research Question to Research Methodology

University of Minnesota. Evidence-Based Practice: Appraising the Evidence. Retrieved from https://pressbooks.umn.edu/evidencebasedpractice/chapter/appraising-the-evidence/ October 17, 2024

The third EBM step is Critical Appraisal of evidence quality

It's necessary to ensure that you critically appraise the resources you identified and acquired before using it to make decisions, especially with regards to clinical care of patients.

First, identify resources at the highest level of evidence to address your research question.

Second, appraise the quality of the research methods and evidence of the resource. Areas to consider for appraisal include:

1. Relevance and Applicability
2. Accuracy
3. Reliability
4. External validity

JAMA Evidence is the gold standard resource training medical practitioners on critical appraisal skills.

CEBM Checklists are extremely helpful checklists for evaluating research quality by study type. For example, the CEBM checklist for RCTs asks includes questions to appraise if patients were randomized, if the patients and researchers were blinded, and more.

Apply is the fourth EBM step

In the fourth step of EBM, a clinician integrates evidence with clinical expertise with patient qualities to identify the best decision for the patient outcomes. Considerations in this step include

• Relevance and quality of evidence
• Quality of life
• Potential harm
• Cost benefit analysis
• Availability of resources
• and more

Assess is the fifth step of EBM

After you have completed the first four steps, the final step that remains is to realize that there is no final step. Rather, this is a continuous process in which you continuously, iteratively evaluate the outcomes of your work, identify further information needs, learn and build on your knowledge by ensuring that you stay up-to date, and more.

University of Minnesota. Evidence Based Practice: Assessing the Evidence. Retrieved October 17, 2024 from https://pressbooks.umn.edu/evidencebasedpractice/chapter/assessing-the-evidence/

Why Evidence-Based Medicine?

Evidence-Based Medicine is about Quality. 

Systematic Reviews

Systematic reviews were first developed in the field of medicine in the 1970s. Systematic Reviews were developed to communicate the highest quality of evidence for medical practitioners to make informed decisions for quality patient care while also reducing the overall burden on the medical practitioners' time.