Applied Evidence Based Medicine
Objectives
- Understand how to use PICO to formulate a prognosis question
- Become familiar with pre-appraised clinical tools
- Know where to look for prognostic decision tools
PICO for Prognosis Questions
When using PICO to frame a prognosis question, the P is the patient, population, or problem; the I is the prognostic factor; the C is usually not applicable; and the O is the outcome of interest (e.g., mortality, recurrence). Many prognosis questions only require a population and an outcome because they often relate to broad populations rather than comparing subgroups.
Here are a couple of prognosis scenarios and how you would break them down using PICO:
Scenario 1: Your patient is a 70-year-old man who was recently diagnosed with dementia, most likely Alzheimer's. He comes to his appointment with his daughter who wants information on the progression of the disease and whether it will increase his risk of death. Her father has named her as his decision-maker for personal care and finances. She wants to start planning for his future care as he has been living alone.
P: elderly man with newly diagnosed dementia
I: (not applicable)
C: (not applicable)
O: risk of death
Clinical Question: In a 70-year-old man with newly diagnosed dementia, what is the risk of death?
Scenario 2: The parents of a 25-year-old patient with schizophrenia are concerned about their son's future health. They ask you about the possibility of relapse.
P: 25-year-old male with schizophrenia
I: (not applicable)
C: (not applicable)
O: relapse
Clinical Question: What is the likelihood of relapse in a 25-year-old with schizophrenia?
Resources for Understanding Prognosis Studies
- Chapter 6. In: Straus SE, Glasziou P, Richardson WS, Haynes RB. Evidence-Based Medicine: How to Practice and Teach It. 5th ed. Edinburgh: Elsevier; 2019.This chapter provides an introduction to evaluating prognosis evidence for its validity, importance, and relevance.
- Chapters 14-17. In: Guyatt G, Rennie D, Meade MO, Cook DJ. eds. Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice, 2nd ed. New York, NY: McGraw-Hill; 2008.These chapters discuss how to find and assess evidence for a prognosis question, delving into genetic association and clinical prediction models.
- Moons KGM, Royston P, Vergouwe Y, Grobbee DE, Altman DG. Prognosis and prognostic research: what, why, and how? BMJ. 2009;338:b375This article considers the principles of prognosis and multivariable prognostic studies, along with the reasons for and settings in which multivariable prognostic models are developed and used.
- Cardarelli R, Oberdorfer JR. Evidence-based medicine, part 5. An introduction to critical appraisal of articles on prognosis. J Am Osteopath Assoc. 2007;107(8):315-319.This article provides an introductory, step-by-step process to appraise an article on prognosis, including the process of assessing its validity, determining its importance, and applying it to an individual patient.
- Mak K, Kum C. How to appraise a prognostic study. World J Surg. 2005;29(5):567-569.This article reviews how to appraise a prognostic study, which involves determining the internal validity of the study design and evaluating the influence of systemic errors or bias.
- Centre for Evidence-Based Medicine Prognosis Critical Appraisal WorksheetUse this worksheet to appraise prognostic studies.
- Last Updated: Sep 6, 2023 5:34 PM
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