In God we trust (motto on US banknotes)… everything else needs evidence

Paraphrasing Hui Lee, 2002

David L. Sackett

Clinical decision

Clinical expertise

Scientificevidence

Patient’spreference

Clinical problem

Evidence based medicine Science and Art of Medicine

Well-built clinical question

The first step in EBM

ASSESSthe patient

1. Start with the patient -- a clinical problem or question arises from the care of the patient

ASK the question

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

ACQUIREthe evidence

3. Select the appropriate resource(s) and conduct a search

APPRAISEthe evidence

4. Appraise that evidence for its validity (closeness to the truth) and applicability (usefulness in clinical practice)

APPLY:talk with the patient

5. Return to the patient -- integrate that evidence with clinical expertise, patient preferences and apply it to practice

Self-evaluation

6. Evaluate your performance with this patient

The steps in EBM

Anatomy of a good clinical question‘PICO’

Types of questions

Study designs for questions

The evidence pyramid

Clinical question for our patient…

Case 1 : Tamiflu for seaonal fluASSESSthe patient

1. Start with the patient -- a clinical problem or question arises out of the care of the patient

You just graduated from medical school and are getting ready to start your internship. Your brother calls you to ask for your advice. He thinks he has the flu. Three of his co-workers are home with the flu and he is sure he has it now. He’s headed to the Urgent Care Clinic but wants to hear from you before he sees the doctor. Should he insist on a prescription to Tamiflu? Will it make him feel better and get back to work sooner? Is it worth the cost?You have heard the reports on the news but need to review the evidence for yourself before advising him. You tell him you will call him right back.

A. Is Tamiflu more effective than bed rest and Tylenol for the flu?

B. How much does Tamiflu cost?C. In healthy adults, does Tamiflu reduce the severity

of acute influenza?

ASKthe Question

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

A. Is Tamiflu more effective than bed rest and Tylenol for the flu?

• Not quite. The question makes a comparison that is not being considered

• B. How much does Tamiflu cost?

• Not again. Though this is an important question, this should be asked only after the question about effectiveness

C. In healthy adults, does Tamiflu reduce the severity of acute influenza?

• Good. This is a well-built clinical question. We know our patient population (healthy adults), our intervention (Tamiflu) and the outcome we want to achieve (reduce the severity of illness)

Case 2 : Acupuncture for old knee

ASSESSthe patient

1. Start with the patient -- a clinical problem or question arises out of the care of the patient

George is an active 83 year old male. He used to swim three times a week for 45 minutes, garden, and walk to church. But for the last several months, he has had trouble walking and bending his knees. It has made gardening difficult and restricted his daily activities.His family physician made the diagnosis of osteoarthritis and prescribed Voltaren (diclofenac), a nonsteroidal anti-inflammatory drug. He is still in pain and wants to know if acupuncture would help. He says he would like to stay away from more medication. You are not sure about the effectiveness of acupuncture for this patient and need to do a little research before you can address his question.

A. Can acupuncture help an elderly 83 year-old male? B. Is acupuncture or diclofenac effective for a painful

knee? C. In elderly patients with osteoarthritis of the knee,

can acupuncture combined with an anti-steroidal inflammatory agent, improve mobility and reduce pain?

• A. Can acupuncture help an elderly 83 year-old male?

• This question is too vague. We still need to know why the patient needs therapy. We also have to know what the therapy will do to the patient (outcome)

• B. Is acupuncture or diclofenac effective for a painful knee?

• Not quite. This question is misleading and implies that the treatment is either acupunture or diclofenac.

• C. In elderly patients with osteoarthritis of the knee, can acupuncture combined with an anti-steroidal inflammatory agent, improve mobility and reduce pain?

• Good. We know the patient problem (OA knee), the intervention (Acupuncture or NSAID) and the expected outcome (improved mobility and reduced pain).

Acknowledgment

• Duke University Medical Center Library (http://www.hsl.unc.edu/Services/Tutorials/EBM/index.htm

)

• Duke University Medical Center Library (http://www.hsl.unc.edu/Services/Tutorials/EBM/index.htm

)