critical Appraisal 'Prognosis

8/13/2019 critical Appraisal 'Prognosis'

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Yuki Yunanda



2

Biologic

onset

ClinicalDiagnosis

OutcomeRecoveryDisability

Deathetc

Natural history of diseases

Clinical courses

(no medical intervention)



Critical Appraisal : Prognosis

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a) Was a defined, representative sample of patients

assembled at a common (usually early) point in the courseof their disease?

b) Was the follow-up of the study patients sufficiently long

and complete?

c) Were objective outcome criteria applied in a ‘blind’fashion?

d) If subgroups with different prognoses are identified, wasthere adjustment for important prognostic factors andvalidation in an independent “test set” patients?

1.1. Are the results of the study valid? Are the results of the study valid?

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See “Introduction”Pg. 2 col. 2



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See MethodsPg.2 Col. 2 Pr. 1



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See “Methods”

Pg. 2 Col. 2 Pr. 5 & 6



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• To minimize the effects of bias in measuring the outcome,investigators should established specific criteria to defineeach important outcome and then used them throughout

patient follow-up. *• In valid studies, investigators making judgments about

clinical outcomes are kept “blind” to these patients clinicalcharacteristics & prognostic factors.*

*(Straus, SE, Richardson, SE, Glasziou, P, Haynes, RB. Evidenced-Based Medicine: How to Practice and Teach EBM )



• In administrative databases, those who record outcomedata will always be unblinded, (and those who record predictor data, always blinded) but will be unaware of the

hypotheses of future investigators making use ofdatabase. **

• One relatively easy safeguard that you can use is to leavedata collection personel unaware of study hypotheses. **

• **(Guyatt, G. Determining Prognosis and Creating Clinical Rule Decision in Clinical Epidemiology: How to Do Clinical Practice

Research , 3rd

edition, 2006. p338-339) .





See “Methods”

Pg. 2 Col. 2 Pr. 5



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See “Table 1” Pg. 5



See “Methods”

Pg. 3 Col.1 Pr. 3 & 4





• % of outcome of interest at a particular point intime (1, 5, 10 etc. survival rates,

• Mean, Median time (length of the follow-up bywhich 50% of patients have died) of the outcome• Event curves• Effect size (Hazard ratio, Rate ratio, Odds ratio,

etc.)

2.(a) How likely are the outcome over time?2.(a) How likely are the outcome over time?

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2. Are the results of this study important?2. Are the results of this study important?



2. Are the results of this study important?2. Are the results of this study important?



a) Is my patient so different from those in the study that itsresults cannot apply?

b) Will this evidence make a clinically important impact on myconclusions about what to offer or tell my patient?

3. Can I apply this valid, important evidence3. Can I apply this valid, important evidence

about prognosis to my patient?about prognosis to my patient?

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Glasser, SP, Cutter,G. Association, Cause and Correlation in EssentialClinical Research . Springer. 2008.



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critical Appraisal 'Prognosis