A Worksheet for Evidence-based Medicine

Step 1: Define a clinical question

PICO (Patient or Problem; Intervention; Comparison Intervention; Outcome)

Your Question:

Step 2: Find evidence

Search Terms Used:

Citation:

Step 3: Assess Evidence

Brief Summary of the Methods:

Are the results likely to be valid?

Question Yes No
Was the assignment of patients to treatment randomized?
Was the follow-up of patients sufficiently long and complete?
Were the patients analyzed in the groups to which they were randomized?
Were the patients and clinicians kept blind to treatment?
Were the groups treated equally, apart from the experimental therapy?
Were groups similar at the start of the trial?

Any validity concerns? If yes, explain.

The magnitude of the treatment effect:

Outcome used for treatment:

Experimental treatment:

Control treatment:

If the study results report outcomes in numbers of patients, fill in the 2x2 table OR event rates below:

  Outcome Present Outcome Absent
Treatment a b
Control c d

Please select the appropriate condition that applies to your data:

- The experimental treatment reduces the risk of a bad event
- The experimental treatment increases the possibility of a good event

Experimental Event Rate (EER)=a/a+b %
Control Event Rate (CER)=c/c+d %
Number of patients in experimental group

Number of patients in control group


Please select the appropriate condition that applies to your data:

- The experimental treatment reduces the risk of a bad event
- The experimental treatment increases the possibility of a good event

The experimental treatment reduces the risk of a bad event The experimental treatment increases the possibility of a good event
RR (risk reduction) =EER/CER


RRR (relative risk reduction) =1-RR or [CER-EER]/CER


ARR (absolute risk reduction) =[CER-EER]


NNT=1/ARR


RBI (relative benefit increase) [EER-CER]/CER


ABI (absolute benefit increase) [EER-CER]


NNT=1/ABI

What is the precision of the treatment effect?

95% Confidence Interval for NNT to

If the study results are reported as intermediate outcomes, and you can't use the above table, report results and significance of findings below:

Any concerns about assessing the evidence? If yes, explain.

Step 4: Apply the evidence to your patient

Question

How is your patient similar to the study population? How is your patient different? Will the differences affect the applicability of the study's result to your patient?

Is the treatment available and affordable to your patient? What is the estimated cost?

What are your patient's potential benefits and harms from the therapy?

Based on this evidence, what would you recommend? Why?

Press CTRL-P to print this worksheet.

Adapted from: Sacket DL et al. Evidence-based Medicine: How to practice and teach EBM. 3rd Edition. Churchill Livingstone. 2000.