Research Guides: Evidence-Based Medicine: Clinical Research

Using the Evidence in Clinical Practice & Research

Clinical Questions

Background Questions	Foreground Questions
Background questions ask for general information about an illness, condition, disease, process or test. Encyclopedias, textbooks and monographs can be consulted for answering background questions.	Foreground questions ask for specific information about a clinical situation. Often, foreground questions compare interventions. Medical literature must be consulted for answering foreground questions.

Clinical Question Domains

Six clinical domains designate the investigative purpose of foreground questions and suggest which study design is best suited to provide answers.

Domain	Purpose	Suggested Study
Cost-Analysis	Determines which treatment or test is most cost effective and least harmful for the patient.	Economic Analysis
Diagnosis	Determines which test is most accurate in diagnosing a condition.	Prospective blind comparison to gold standard
Etiology/Harm	Determines causes or risk factors of a condition.	RCT ⇒ Cohort ⇒ Case Control ⇒ Case Series
Prevention	Determines how to reduce chance of condition by identifying and modifying risk factors and how to diagnose early by screening.	RCT ⇒ Cohort ⇒ Case Control
Prognosis	Determines the clinical course over time and possible complications of a condition.	Cohort ⇒ Case Control ⇒ Case Series
Therapy/Intervention	Determines which intervention results in the best outcome.	RCT
Qualitative/Meaning	Investigates patient experience (perceptions, attitudes, beliefs).	Cross-Sectional

Notes:

Secondary literature is preferred but not always available
⇒ move to next study type if suggested type is not available
RCT - Randomized Controlled Trial

Types of Information

Non-Appraised & Preappraised

In evidence-based medicine, scholarly literature is grouped by the presence or absence of critical appraisal. Critical appraisal is the process of assessing and interpreting research by systematically considering its validity, results, and relevance. Research that has been critically appraised is labeled Pre-appraised (a.k.a., Filtered and Processed). Research that has not been critically appraised is labeled Non-Appraised (a.k.a., Unfiltered and Non-Processed).

Generally, primary literature is Non-Appraised at the individual article level. Secondary literature is sometimes Pre-Appraised. Examples of Pre-Appraised evidence include, Systematic Reviews, Meta-Analysis, Critically Appraised Topics, and Clinical Guidelines. Please note that traditional Review articles, which are secondary in nature, are not Pre-Appraised.

Pre-Appraised sources of evidence are not available for every clinical situation. When this type of evidence is not available on a situation/topic, primary literature must be identified and critically appraised by the clinician (follow the EBM practice Model).

Developing Clinical Questions

How to Ask a Clinical Question

A good clinical question must identify and consider particular pieces of information about the clinical situation. The PICO Framework is highly recommended for developing clinical questions. PICO is a mnemonic outlining the information essential for finding strong evidence.

The PICO Framework

P	Patient or Problem	Who is the patient or what is the problem? What are the important characteristics?
I/E	Intervention OR Exposure	What intervention will be investigated? The intervention might be a treatment, therapy, lifestyle change, or prognostic factor. What potentially harmful factors will be investigated?
C	Comparator	What alternative is being investigated? [This element is optional. When included, it is often the standard intervention]
O	Outcome	What outcome is desired? The clinician might want to measure or improve a patient's health situation or some other aspect of the clinical situation.

A T is sometimes included in the framework to indicate that time is significant to the clinical situation, or it can represent Type of Study.

T	Time	Is there a Time frame to consider? [This element is optional as it may not be an important factor in the investigation]
T	Type of Study	Which study design is best suited to answer the clinical question.