There are two types of questions that you encounter in your medical education and medical practice: background and foreground.
Background questions are needed to acquire basic or general knowledge about a topic. These are the who, what, why, when, where, and how questions. For example: What are the major complications of diabetes? Who should be tested for osteoporosis? When should children get the Varicella vaccine? How do cancer cells grow and spread?
Foreground questions seek information to help make a clinical decision focused on a particular patient or clinical situation.
In order to practice evidence-based medicine, you need to be able to formulate a good clinical question. It is helpful to use the PICO(T) format. With PICO(T), you divide your topic into its key concepts, formulate your clinical question, and develop a search strategy.
P - Patient or Problem
I - Intervention, Exposure, or Prognostic Factor
C - Comparison, if any
O - Outcome
T - Type of Question
Case: Your patient is a 55 year old woman. She was diagnosed with osteoporosis based on the results of her bone density scan. She is 5'1" and weighs 90 lbs. Her medical history is remarkable only for 2 normal pregnancies and menopause at age 53. She is not a smoker or a drinker of alcohol. Her mother also had osteoporosis and passed away at age 87. . . . Your patient is reluctant to take a treatment drug because she prefers natural approaches. She asks if she could delay taking a drug for now, and try natural approaches to see if that helps stop the progression of her osteoporosis.
|Patient or Problem||Intervention||Comparison||Outcome||Type of Question|
|Describe the characteristics of the patient/population/problem in your case. What is the problem, disease, or condition? What demographics are important for this case - age, ethnicity, gender?||What is the specific treatment, medication, procedure, diagnostic test, prognostic factor, exposure?||Are you comparing the intervention to an alternative intervention, a gold standard, or placebo?||What is the outcome(s) you want to look at? These could be patient-oriented outcomes such as quality of life, measures such as lab values, or other qualitative or quantitative outcomes.||Is this a therapy, diagnosis, prognosis, harm, etiology, prevention, cost-analysis, or value based care question?|
|55 year old woman with osteoporosis||natural approaches - calcium, vitamin D, weight bearing exercise||drug treatment - bisphosphonates||prevent further bone loss||therapy / intervention|
Based on the table above, our clinical question is: For a 55 year old woman with osteoporosis, is a regimen of calcium, vitamin D, and/or weight bearing exercise as effective as treatment with bisphosponates in preventing additional bone loss?
The type of question influences the type of study design:
|Type of Question||Type of Study|
|Treatment/Therapy||Randomized controlled trial > Cohort study > Case Control > Case series|
|Harm/Etiology||Cohort study > Case control > Case series|
|Prognosis||Cohort study > Case control > Case series|
|Prevention||Randomized controlled trial > Cohort study > Case Control > Case series|
|Diagnosis||Prospective, blind comparison to a gold standard or cross-sectional|
|Quality of Life||Qualitative|
If many research studies exist on the topic, you may discover that a systematic review, a meta-analysis, or current guidelines have been published to answer your question.
Systematic review - a summary of similar research studies which answer a specific clinical question. This type of review uses explicit methods to perform a thorough literature search. The details of the search, a critical appraisal of the individual studies, and a recommendation for clinical practice can be found in the article.
Meta-analysis - A review of the literature that uses quantitative methods to summarize the pooled results of the studies. The studies can come from a systematic review or from a different defined group of studies.
Guidelines - As defined by the Institute of Medicine (IOM), "Clinical practice guidelines are statements that include recommendations intended to optimize patient care. They are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options. Because of the large number of clinical practice guidelines available, practitioners and other guideline users find it challenging to determine which guidelines are of high quality."1 In its report Clinical Practice Guidelines We Can Trust, the IOM presents recommended standards for determining the quality of clinical practice guidelines. 1 The standards may be found here.
1. Institute of Medicine. Clinical Practice Guidelines We Can Trust: Report at a Glance. 2011, March 23. http://www.nationalacademies.org/hmd/Reports/2011/Clinical-Practice-Guidelines-We-Can-Trust.aspx
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