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Library Resources for Medicine: Evidence-based Medicine and Research

This guide links to eBooks used in the Elson S. Floyd College of Medicine organized by subject.

Looking for Evidence Synthesis Services at WSU?

Five Steps of Evidence-Based Medicine

EBM commonly consists of five steps, which are often referred to as the "5 A's of EBM": graphic showing the five steps of evidence-based medicine

1. Ask

Construct an answerable question using the PICO framework or other clinically appropriate approach.

2. Acquire

Convert your question to a search strategy and locate the best evidence.

3. Appraise

Critically evaluate the evidence for reliability and validity.

4. Apply

Integrate the evidence with patient preferences and clinical experience.

5. Assess

Determine the effectiveness of the process for improving patient care and outcomes.

Goal of a search strategy

Precision = Number of relevant documents retrieved / Total number of documents retrieved.

Recall = Number of relevant documents retrieved / Total number of relevant documents in the corpus.

ACQUIRE: Using PICO to translate a question into search strategy

The PICO Framework helps clinicians design an answerable question by breaking the clinical problem into searchable concepts. A complete search of the literature is needed to determine the best evidence to answer a question.

P: patient, population, problem

I: intervention, exposure

C: comparison or alternative treatment

O: outcome being measured

Identify "synonymous" terms and phrases found in the literature

  • May be spelling variants, historical terms, mechanisms of action of drugs, disease names and causative agents, opposites, proprietary and generic names, outcome and measurement tool
  • Controlled vocabulary used by the database
  • Use quotation marks around multiple-word phrases
  • Truncate with an asterisk the end of the last term to find plural and singular, however truncation in PubMed will turn off PubMed AI (automatic term mapping)

Combine like terms and phrases for a single concept with the Boolean OR, then combine concepts with AND

ACQUIRE: Narrow Search to Higher Levels of Evidence

Once you have developed a complete search strategy then use the following database features to narrow results to higher levels of evidence relevant to your question.

  • sort
  • limiters/filter (date, study type, etc.)

Types of Questions with a PICO Template and Ideal Study Type to Answer the Question

 

Type of Question Description Template Type of Study
Etiology/Exposure/Harm Does this intervention/exposure cause this condition?​ Are (patient) who have (intervention/exposure), compared with those without (comparison) at (more/less) risk for (outcome)?​ RCT>cohort>case control>case series​
Diagnostic  How accurate is this diagnostic test?​ In (patient) are/is (intervention) compared with (comparison) more accurate in diagnosing (outcome)?​ Independent, blind comparison to gold standard (cross-sectional)​
Treatment Is this intervention more effective than another?​ In (patient and/or problem), how does (intervention) compared with (comparison intervention) affect (outcome)?​ RCT
Prognostic What is the likely outcome, progression or survival time for this condition?​ In (patient) how does (intervention/exposure) compared with (comparison) influence (outcome)?​ Cohort>case control>case series​

 

Levels of Evidence Table designed to help visualize value of any given type of resource in descending order to answer a clinical question based on the 6S Evidence Pyramid incorporating pre-appraised evidence.

Level of Evidence Description Example Resources to Search

Systems

(Highest Level)

Evidence combined with EHR patient data using standard data structure and terminology Computerized Decision Support embedded in EHR using FHIR HL7 and SNOMED CT
Summaries

Guidelines

Point of Care Tools rank levels of evidence for recommendations using standard GRADE

ECRI Guidelines

UpToDate, DynaMed

Synopses of Syntheses Umbrella Reviews Health Evidence
Syntheses

Focus on a specific clinical question

Meta-analyses of RCTs

Systematic Reviews

 

Cochrane Library

Synopses of Studies Critical Appraisal of single studies ACP Journal Club
Primary Studies RCT > Cohort > Cross-sectional > Case-Control > Case series/Case report PICO search of databases PubMed, EMBASE, APA PsycInfo, etc.

Expert Opinion

(Lowest Level)

Provide a general overview of foundational science, systems, diseases and symptoms. Often the best source for an overview of a large topic and background information that does not change frequently. Not a good source for new diseases, new diagnostic tests, new treatments, or co-morbidities and confounders. References can point toward higher levels of evidence but have the potential to be "cherry picked." The search is not reproducible, not assessed for risk of bias, and levels of evidence for recommendations are not ranked using a standard system. Textbooks, Step Prep, Review Articles

Below the pyramid: Blogs, Wikipedia, Organization web sites, Trade journals, Discussion boards

Haynes R. B. Of studies, syntheses, synopses, summaries, and systems: the "5S" evolution of information services for evidence-based healthcare decisions. Evidence-based medicine,. 2006; 11(6), 162–164. https://doi.org/10.1136/ebm.11.6.162-a ​ ​ ​

Dicenso A, Bayley L, Haynes RB. Accessing pre-appraised evidence: fine-tuning the 5S model into a 6S model. Evid Based Nurs. 2009;12(4):99-101. https://doi.org/10.1136/ebn.12.4.99-b

Example PICO search

Step 1 Ask

For patients aged 65 years or older (P), how does the use of an influenza vaccine (I) influence the risk of developing pneumonia during the flu season (O)? [The comparison (C) is not receiving an influenza vaccine]

Step 2 Acquire

Identify synonymous terms and controlled vocabulary found in the literature

P:  Aged OR elderly OR geriatric OR "older adult*"

I:  "Influenza Vaccines"[Mesh] OR ((flu OR influenza)(vaccin* OR immunization*))

C:

O "Pneumonia"[Mesh](risk OR prevent*)

Search Strategy: ("Aged"[Mesh] OR elderly OR geriatric OR "older adult*") AND ("Influenza Vaccines"[Mesh] OR ((flu OR influenza)(vaccin* OR immunization*))) AND ("Pneumonia"[Mesh](risk OR prevent*))

Limit to last 10 years, and higher level studies appropriate to the question 

Step 3 Appraise

  • Evaluate the journal quality
  • Evaluate the author(s) for risk of bias
  • Critically appraise the literature

Step 4 Apply

  • Integrate evidence with patient data to support clinical decisions

Step 5 Assess

  • Are there lessons learned to improve future care?

 

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