What is and how to make a PICO question

See this topic in the GRADE handbook: Framing the health care question

GRADE guidelines article: 2. Framing the question and deciding on important outcomes  
(The GRADE workinggroup official JCE series)

"A well-accepted methodology associated with framing of questions addressing alternative management strategies in systematic reviews mandates carefully specifying the patient population, the intervention of interest, the comparator, and the outcomes of interest. The value of the methodology—popularly known as PICO (patient/intervention/comparator/outcome)—in helping achieve focused recommendations is increasingly recognized not only by systematic review authors but also by guideline developers.

A guideline question often involves another specification: the setting in which the guideline will be implemented. For instance, guidelines intended for resource-rich environments will often be inapplicable to resource-poor environments. In the first article in this series, we presented an evidence profile describing the impact of antibiotics on otitis media. The results apply to high- and middle-income countries, in which the risk of progression to mastoiditis is very low.

The most challenging decision in framing the question is how broadly the patients and intervention should be defined. For example, in addressing the effects of antiplatelet agents on vascular disease, one might include only patients with transient ischemic attacks; those with ischemic attacks and strokes; or those with any vascular disease (cerebro-, cardio-, or peripheral vascular disease). The intervention might be a relatively narrow range of doses of aspirin, all doses of aspirin, or all antiplatelet agents.

On what basis should systematic-review authors or guideline developers make this decision? The underlying biology must suggest that, across the range of patients and interventions, it is plausible that the magnitude of effect on the key outcomes is more or less the same. If that is not the case, the review or guideline will generate misleading estimates for at least some subpopulations of patients and interventions.

For instance, if antiplatelet agents differ in effectiveness in those with peripheral vascular disease vs. those with myocardial infarction (as one study of clopidogrel vs. aspirin that enrolled patients from both populations suggested), a single estimate across the range of patients and interventions will not well serve the decision-making needs of patients and clinicians. The same will be true if different antiplatelet agents have differing magnitudes of effect."

Go to the orginal article for full text, or go to a specific chapter in the article:

Structured questions of patient management
Framing questions involves specifying patients, interventions, comparators, and outcomes, and sometimes setting
Ensuring the question framing is appropriately specific
Specification of outcomes: ensuring comprehensiveness
Outcome importance: three categories
Outcome importance: influence of perspective
Importance of outcomes: using evidence
Outcome importance: missing evidence and surrogate outcomes
Outcome importance: preliminary and definitive ratings

Intro to Choosing a comparison and outcomes for the Summary of Findings Table from McMaster University CE&B GRADE pages: http://fhsed.mcmaster.ca/onlineModules/GRADE/outcomes/

Interested in linked data?
Take a look at this presentation about linkedPICOs

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