The second step in Evidence-Based Medicine is to ask a clinical question. This is one of the most crucial steps in the EBM process as it will help you formulate your search strategy, what resources you will use, what evidence is most appropriate for your investigation, and initiate the appraisal process. Within this step, you will formulate a specific, relevant, clinical question. This process is facilitated by the PICO method.
A well-built clinical question is key to evidence-based decision making.
The PICO method is a way to not only help you form specific questions but is also a way to formulate a database search strategy. The PICO mnemonic helps you to identify the key concepts that need to be in articles in order to answer your clinical question.
| P: Population, Patient, or Problem | How would you describe a group of patients similar to yours? What are the most important characteristics of the patient? What is the condition or disease you are interested in?. |
| I: Intervention, Prognostic Factor, Exposure | What main intervention or exposure you are considering? What do you want to do with the patient? What is the main alternative being considered? |
| C: Comparison | What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, etc.? Can be none or placebo |
| O: Outcome | What are you trying to accomplish, measure, or affect? Can be disease-centered or patient-centered. |
| T: Time* |
How much time does it take to demonstrate the clinical outcome? How long it takes for an intervention to achieve the outcome? How long participants are observed? |
*Not every question will have a time component.
After using PICO you will have all the elements necessary to formulate a specific, relevant clinical question. Questions will include all the elements of PICO that you pulled from the clinical scenario. Everyone will "see" a different way to write out the clinical question. Below is a formula you can use to build clinical questions using PICO until you get comfortable.
In _________ (P), what is the effect of ___________ (I) compared to ______________ (C) on ______________(O) over _______ (T)*
*Remember that Time is not always necessary, often it is conveyed or understood from the question.
Clinical questions can further be classified into their domain or type, what aspect of medical care the question investigates. Different types of research studies are better suited to answering questions in different domains and can help you focus your questions and search strategy.
ALL foreground questions are best answered by well-done Meta-Analyses, Systematic Reviews, or Evidence-Based Practice Guidelines.
| Type or Domain | Explanation | Types of evidence to answer the question |
|---|---|---|
| Therapy(Treatment) | Questions about the effectiveness of interventions in improving outcomes in sick patients/patients suffering from some condition. These are the most frequently asked. Among the many treatments offered by clinicians are medications, surgical procedures, exercise, and counseling about lifestyle change | Randomized Control Trials (RCTs) |
| Prevention | Questions about the effectiveness of an intervention or exposure in preventing morbidity and mortality. Similar to treatment questions. When assessing preventive measures, it is particularly important to evaluate potential harms as well as benefits. | RCT Prospective Study |
| Diagnosis | Questions about the ability of a test or procedure to differentiate between those with and without a condition or disease |
RCT Cohort Study |
| Prognosis (Forecast) | Questions about the probable cause of a patient's disease or the likelihood that he or she will develop an illness |
Cohort Study Case-Control Study Case Series |
| Etiology/Harm (Causation) | Questions about the harmful effect of an intervention or exposure on a patient. |
Cohort Study Case-Control Study Case Series |
| Meaning | Questions about patient's experiences or concerns | Qualitative Studies |
Knowing that some study designs are better suited for particular clinical question types, we can think of evidence being arranged in a hierarchy or pyramid. The hierarchy is pyramid shaped because as the study design becomes more rigorous, fewer of these types of studies are created. The most robust evidence, meta-analyses and systematic reviews, are at the top of the evidence pyramid, regardless of which pyramid you choose. The pyramid we are using includes filtered, secondary sources and clinical guidelines.
Remember that ALL clinical questions are best answered by meta-analyses, systematic reviews, or clinical guidelines.
Clinical Scenario: Sheldon and Amy's baby, Kirk, was born prematurely. After speaking with other preemie parents, they are concerned about whether Kirk will be at a greater risk, over his lifetime, of sensory deafness, than full-term babies.
| Elements of a Good Clinical Question |
Patient, Population, or Problem |
Intervention, Treatment, Prognostic Factor,Exposure |
Comparison | Outcome |
|---|---|---|---|---|
| Your Case | INFANT | PREMATURE | FULL-TERM | SENSORIAL DEAFNESS |
PICO/Clinical Question: In infants, what is the effect of premature birth compared to full-term birth on sensory deafness over the lifespan?
Domain: Prognosis
Evidence Types: Systematic Review, Meta-Anaylsis, Cohort Studies, Case-Control Studies
Clinical Scenario:
Your next patient is an 86-year-old woman with coronary artery disease. She is accompanied by her daughter, who is also her caregiver. Her daughter mentions to you that she was doing some online research and read that aspirin was a more effective drug at reducing the likelihood of stroke. She wants to know if her mother should stop her Heparin and take aspirin instead, she also mentions that stopping Heparin could save her a great deal of money.
| Elements of a Good Clinical Question | Patient, Population, Problem |
Intervention, Exposure, Prognostic Factor |
Comparison | Outcome |
| Your Case |
Clinical Question:
Question Type:
Evidence Type(s):