Every time we see a patient, we need new information about some element of the diagnosis, prognosis or management. Because our time to try to find this information is often limited, we need to be very efficient in our searching. To achieve this efficiency, we need to become skilled at formulating clinical questions.

Tips on How to Formulate Questions

Consider the questions that arise from the following scenario:

You admit a 65 year old man with a stroke. On examination you find that he has mild weakness of the right arm and right leg and bilateral carotid bruits. You send the patient for carotid doppler ultrasonography and subsequently receive the report that he has moderate stenosis (50-69% by NASCET criteria) of the ipsilateral carotid artery. You’ve noticed in the pile of journals that is accumulating in your office that there has been some recent literature addressing surgical versus medical therapy for patients with symptomatic carotid stenosis but you are unsure what the results of these studies indicate.

Think about this scenario and about what questions arise from it. Write down your questions on a piece of paper.

When this patient scenario was encountered on our clinical service, the housestaff generated several clinical questions including:

  1. Can ASA decrease the risk of stroke?
  2. Does a carotid bruit predict significant carotid stenosis?
  3. How effective is a carotid endarterectomy in someone with moderate carotid stenosis?

Note that these questions ask for specific knowledge about the diagnosis and management of the patient. Well-built clinical questions should have 4 components

Patient or Problem
Description of the patient or the target disorder of interest.
Intervention
Could include: Exposure, Diagnostic test, Prognostic factor, Therapy, Patient perception etc.
Comparison Intervention
Relevant most often when looking at therapy
questions
Outcome
Clinical outcome of interest to you and your patient

Returning to the 3 questions that we posed above, how can we make them into well-built clinical questions?
Let’s look at the first question:

Patient or Problem
65 year old man with a stroke and moderate carotid stenosis.
Intervention
ASA
Comparison Intervention
Placebo
Outcome
Stroke

Now we can use this to formulate our clinical question:

In a 65 year old man with a stroke and moderate carotid stenosis, can ASA decrease the risk of another stroke compared with no treatment?

Try formulating a well-built question yourself using the last 2 questions that were posed by our housestaff.

  • Does a carotid bruit predict significant carotid stenosis?
  • How effective is a carotid endarterectomy in someone with moderate carotid stenosis?

Write your questions down on a piece of paper.

Compare your questions to the questions we formulated:
Does a carotid bruit predict significant carotid stenosis?

Patient or Problem
65 year old man with a stroke
Intervention
Carotid bruit
Comparison Intervention
Doppler ultrasonography or angiography
Outcome
Carotid stenosis

In a 65 year old man with a stroke, how precise and accurate is the presence of an ipsilateral carotid bruit for diagnosing significant carotid stenosis compared with doppler ultra sonography?

  • Note: there are other variations of this question; for example, we could have asked about angiography.
  • How effective is a carotid endarterectomy in someone with moderate carotid stenosis?
Patient or Problem
65 year old man with stroke and moderate carotid stenosis
Intervention
Carotid endarterectomy
Comparison Intervention
Medical therapy
Outcome
Stroke

In a 65 year old man with stroke and moderate carotid stenosis, can carotid endarterectomy decrease the risk of stroke compared with medical therapy?

  • Note: there are variations for this question; for example we could have asked about other outcomes like death.

Further Reading

  • Sackett DL, Straus SE, Richardson WS, Rosenberg W, Haynes RB. Evidence-based medicine: How to practice and teach EBM. Chapter 2. Churchill Livingstone:Edinburgh, 2000
  • Richardson WS, Wilson MC, Nishikawa J, Hayward RSA. The well-built clinical question: a key to evidence-based decisions [Editorial]. ACP J Club 1995; 123: A12 – A13.
  • Richardson WS. Ask, and ye shall retrieve [EBM Note]. Evidence Based Medicine 1998; 3: 100 – 101.