Introduction to Evidence-Based Practice

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The Well-Built Clinical Question

ASSESS
the Patient

1. Start with the patient: a clinical problem/question arises from the care of the patient

ASK
the Question

2. Construct a well-built question derived from the case

EBM always begins and ends with the patient. To begin this process, consider the following clinical scenario:

This is a new patient who recently moved to the area to be closer to her son and his family. Pauline is 73 years old and has a history of congestive heart failure and a left ventricular ejection fraction of 40%.

She has been hospitalized twice within the last 9 months for worsening of heart failure. She is extremely diligent about taking her medications (enalapril, aspirin and simvastatin) and wants desperately to stay out of the hospital. She lives alone with several cats and a canary.

She comes to you with an advertisement for Avapro (Irbesartan) and wants to know if this would help her.  You are not certain of the evidence supporting this drug. You decide to research this question before discussing this with her during the next visit.

Patient

The next step in this process is to take the identified problem and construct a question that is relevant to the case and is phrased in such a way as to facilitate finding an answer.

Anatomy of a good clinical question: PICO

PICO is a mnemonic that helps one remember the key components of a well focused question.  The question needs to identify the key problem of the patient, what treatment you are considering for the patient, what alternative treatment is being considered (if any) and what is the outcome you want to avoid or promote. 

P = Patient or problem

How would you describe a group of patients similar to yours? What are the most important characteristics of the patient? This may include the primary problem, disease, or co-existing conditions. Sometimes the sex, age or race of a patient might be relevant to the diagnosis or treatment of a disease.

I = Intervention, prognostic factor, or exposure

Which main intervention, prognostic factor, or exposure are you considering? What do you want to do for the patient? Prescribe a drug? Order a test? Order surgery? What factor may influence the prognosis of the patient? Age? Co-existing problems? Has the patient been exposed to something? Asbestos? Cigarette smoke?

C = Comparison

What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, a drug and no medication or placebo, or two diagnostic tests? Your clinical question does not always need a specific comparison.

O = Outcomes

What can you hope to accomplish, measure, improve or affect? What are you trying to do for the patient? Relieve or eliminate the symptoms? Reduce the number of adverse events? Improve function or test scores?

The structure of the PICO might look like this:

Patient / Problem

heart failure, ejection fraction 40%, elderly

Intervention

irbesartan or avapro

Comparison, if any

none, placebo, standard care

Outcome

primary: reduce need for hospitalization;
secondary: reduce mortality

 

For our patient, the clinical question might be:

In elderly patients with heart failure and an ejection fraction of 40%, is irbesartan effective in reducing the need for rehospitalization?

Two additional elements of the well-built clinical question are the type of question and the type of study. This information can be helpful in focusing the question and determining the most appropriate type of evidence or study.

Patient

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Revised July 2010