Madigan Faculty Development Fellowship: Tools for Information Mastery
Prognosis Worksheet
Of course, the best-designed study for determining disease prognosis is the randomized controlled clinical trials.
However, due to ethics and practicality (remember the Tuskagee Syphilis Experiment?), it is often not possible.
Cohort and case-control studies provide the strongest evidence after the RCT.
P:_______________
I:______________
C:________________
O:________________
Step 1: Hypothesis generation
What is the purpose of this study?
Step 2: Study design
What type of study is it? If it’s not a cohort study, why not?
Step 3: Study group
What criteria were used to establish a diagnosis of disease (i.e. inclusion criteria)?
What were the exclusion criteria? Why did they exclude these patients?
Was there evidence of referral filter bias?
How does this affect generalizability?
Step 4: Defining outcomes and patient characteristics
What were the outcome(s) of interest, and how were they defined?
What were the prognostic factor(s) studied?
Were the investigators who determined patient outcomes blinded to the prognostic factor(s)?
ADVANCED (Statistics): Did they perform survival curve analysis? If so, did they use a Kaplan-Meier
curve and check ROC? Why?
Step 5: Patient characteristics
Look at the baseline patient characteristics (usually Table 1). Were all study patients at a similar and well-defined
point in their disease?
Were there any baseline differences to assigned groups? If so, did the researchers adjust for these differences?
Step 6: Results
How long did they follow patients? Was the follow up sufficiently long and complete (specifically for the
prognostic factors)?
Were the patients who completed the study different from those lost to follow-up?
References
1. Laupacis A, Wells G, Richardson WS, Tugwell P. Users’ guides to the medical literature. V. How to use an article about
prognosis. JAMA 1994;272:234-7.
Madigan Faculty Development Fellowship: Tools for Information Mastery
What’s the likelihood of the outcome(s) in a specified period of time? How did they measure likelihood of outcome
event (RR, OR, descriptive rate, etc)?
What’s the risk associated with each prognostic factor? (Relative risk, odds ratio)
Look at the Confidence Intervals for the Relative Risks/Odds Ratio. Do any of them cross 1.00? What
does this mean?
Did the investigators report a survival curve analysis? How do you interpret the curve?
Step 7: Discussion of Study
Is this study valid? (Look at Steps 1-5; also see the Prognosis JAMA Worksheet)
Is this study generalizable to our patient population?
Will this affect your clinical practice?
Will these results lead directly to selecting or avoiding therapy?
Are the results useful for counseling or reassuring patients or family members?
For further study, for those interested in research…
During the initial reading, imagine you are the researchers doing the study and see if you would approach it the same
way. Then, after reviewing the article, do an after-action-review and see if you would do anything different
knowing the results.
References
1. Laupacis A, Wells G, Richardson WS, Tugwell P. Users’ guides to the medical literature. V. How to use an article about
prognosis. JAMA 1994;272:234-7.