An introduction to evidence based medicine

Usama M. Fouda

Professor of Obstetrics and Gynecology , Faculty of medicine, Cairo University .

Egypt

What is evidence-based medicine (EBM)?

"A systematic approach to clinical problem solving by the

integration of best research evidence with clinical expertise and

patient values”

(David Sackett, et al. Evidence-based Medicine. How to Practice and Teach EBM, 2000)

"The conscientious, explicit, and judicious use of current best

evidence in making decisions about the care of individual patients”

(Gordon Guyatt, et al. Users' Guides to the Medical Literature, 2002)

2

Is an approach to decision-making

in which the clinician uses the best

evidence available, in consultation

with the patient, to decide upon

the option which suits that patient

best.

May 2, 2023 Evidence Based Medicine 4

The steps of practicing EBM

1. Ask a focused question.

2. Acquire the best evidence.

3. Appraise the evidence.

4. Apply the evidence in practice.

• Amalgamate the valid evidence with other relevant information

(values & preferences, clinical/health issues, & system issues).

5. Assess the effectiveness and efficacy of EBM process( clinical audit).

I) Ask a clinical question in a PICO format

II) Finding the evidence

• Search terms should be referred back to the original PICO

question.

• The process of finding evidence therefore follow three key steps:

A. Identify terms to fit your PICO question.

B. Look for secondary sources.

C. Search for primary sources.

A) Identify terms to fit your PICO question

B) Look for secondary sources

• Guidelines: RCOG Green-top guidelines, NICE, UK National Library

for Health, SIGN, US National Guidelines Clearinghouse; Canadian

Medical Association and New Zealand Guidelines Group.

• Evidence-Based Summaries: Up to date, DynaMed, etc.

• Systematic Reviews: Cochrane Library and systematic review/meta-

analysis/ filters in PubMed.

C ) Search for Primary Sources (Original Studies)

• Search using PubMed, Scopus, Web of science, Embase, etc.

• Use methodological filters to target the right type of study.

For instance, PubMed filters for:

• Therapy , diagnosis, prognosis and etiology.

• Article type ( reviews, RCTs, etc.)

• Publication date

The levels of evidence and their role in EBM

• A cornerstone of EBM is the hierarchical system of classifying

evidence.

• This hierarchy is known as the levels of evidence.

• Physicians are encouraged to find the highest level of evidence to

answer clinical questions.

Oxford Centre for Evidence-based Medicine – Levels of Evidence (March 2009)

III) Critically Appraise the Evidence

• Determine the appropriateness of some evidence for a particular

clinical situation.

• Three main aspects to be appraised: V - I - A

1. Validity: (closeness to the truth).

Internal validity: refers to the soundness of the research

methodology.

External validity: refers to generalizability of the results.

2. Importance.

3. Applicability: (whether can be applied in clinical practice).

IV) Apply the evidence to a particular patient

• Compare the patient with those in the study from which evidence

has been generated (similar disease state, similar baseline

characteristics etc.).

• Consider the patient’s values, beliefs, concerns, affordability,

compliance and readiness for the intervention.

Benefits of adopting EBM

• Minimizes the error and optimizes the quality in patient care.

• Reduces the cost of treatment.

• Helps in advancement of knowledge and keeping pace with

scientific progress.