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Evidence Based Medicine: PICO & Clinical Questions

Introduction to fundamental concepts of evidence based medicine and practice.

Identify Your Question/Problem

The EBM process begins when a clinician (You) is presented with a scenario that has some uncertain end or unanswered question. You will find that while many of the cases that you face as a clinician are routine and have a known trajectory, some cases have an air of ambiguity to them. In these situations it is critical that you are able to define the major and defining characteristics of the case and organize them in a uniform and meaningful way. This separating the wheat from the chaff, as it were, is the first step of the EBM process.

This process involves examining your cases and asking several important questions:

  • Who is the subject of this case?
  • What relevant information do I have about my case subject?
  • What is the ultimate desired end in this case?
  • What kind of question is being asked here (harm, diagnosis, prognosis, therapy)? 

These, as well as other, questions will help you key in on the most salient points within your case. With this done you can then move on to the first steps in assessment and elucidate answers to your question. 

Identify/Searching for Background Questions

What are background questions? These are questions that assist the clinician in filling in the gaps that they may have on a given subject.  These are generally reference-based questions that give either quick or definitional knowledge. Examples include:

  • What is the proper pediatric dosage of armodafinil?
  • When is the most prevalent onset of narcolepsy in females?
  • What is Anaphylactic shock?
  • What is the gold standard for treatment of Epistaxis?

Answering these questions will not only give the clinician a fuller view of the case, but also lead them to new understandings and pathways to answering their case question. 

Formulate Your PICO and Clinical Question

Think of PICO as a way to sift out the most relevant concepts from a scenario and organize them in a clear and logical way. PICO stand for:


P: Patient, Population or Problem

This can refer to a specific patient, such as a 24 year-old male with sore throat and fever, or it can also be a more generalized problem, such as Renal Cancer in Vietnam. Them main emphasis is to describe, briefly, who or what is central to the scenario. It is best, especially when dealing with individuals, to be as specific as possible.

I: Intervention

Classically, this is any diagnostic, prognostic, therapy or other mediating factor in a scenario. This can often be the intervention that is in question, such as a new drug or diagnostic test.

C: Comparison

Your comparison is what is being contrasted to your intervention. In many cases this will be the gold standard. It is important to note that this is not always necessary. So in cases where you may only be examining the effects of a single factor, the comparison can be omitted. 

O: Outcome

Your outcome is whatever end result is most beneficial to your patient. The two most important points for the outcome are that it should be specific to the clinical outcomes for your patient and that it should be as measurable as possible. Typically most outcomes deal with morbidity, mortality or complications. You should also keep any patient preferences and values in mind here. What are the factors that a patient will want in their outcomes? These can be factors such as, ability to maintain lifestyle, pain management or compliance.

T: Type of Study or Type of Question

In some iterations of PICO you will find a ending T which can represent either the best type of study suited to answering the question. Often this will be a primary level study, as all EBM question can be best answered with either a systematic review or meta-analysis (which are secondary level evidence). Additionally, you may also see the T represented as type of question referring to the four general EBM question types of Diagnosis, Prognosis, Harm/Etiology, and Therapy. Knowing the question type can inform what kind of study is best to select or how you may construct your search. 

Using these five factors to make sense of a scenario takes time and effort, but will result in better understanding your scenario and your ability to transfer this knowledge to a searchable entity. 

Example of a PICO:

P: A 17 year-old Spanish male diagnosed with narcolepsy with cataplexy and a family history of narcolepsy

I:  Low carb / high fat diet and additional daily naps

C: Venlafaxine

O: Reduction of daytime sleepiness measured as a 0-10 on the Epworth Sleepiness Scale

T: Type of Question - Therapy / Type of Study - RCT


Clinical Question

Your clinical question is the logical construction of your PICO into sentence structure. It should be very redundant from your PICO and follow the same pattern. You can see from the example below that a well-formed PICO will make constructing a Clinical Question very easy.

In A 17 year-old Spanish male diagnosed with narcolepsy with cataplexy and a family history of narcolepsy will adding low carb / high fat diet and additional daily naps versus Venlafaxine lead to a reduction of daytime sleepiness measured as a 0-10 on the Epworth Sleepiness Scale (ESS)?