drk1980
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A study is done and 50 yr old healthy men were picked randomly and assigned to either get a DRE screening test or New blood test. After 5 yrs 40 out of the 50 from the blood test were living after 2 yrs after being diagnosed in comparison with 15 out of 50 screened with DRE survived 2 yrs after being diagnosed with prostate Ca. Research concluded that Blood test increased survival compared to Rectal exam.
Which of the following potential flows is most likely to invalidate this conclusion?
a. Age of patient
b. Diagnostic Bias
c. Lead time bias
d. recall bias
e. type 2 error
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| mjl1717
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my semieducated guess-type2 error.
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| skyhigh
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c?
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| sarika
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i'll go with lead time bias too
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| ed222
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I will go with diagnostic bias because the stage of CA in either group is hard to be stablished if biopsy is not done. The DRE and PSA can help you to be suspicios but the real diagnosis and grading and staging is with biopsy. I hope I am right.
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| reet
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I guess..B. diagnostic bias
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| druas
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i guess lead time bias...C..
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| Geroo
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I think it's lead time bias.
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| krsna
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must be lead time bias
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| nadiabarati
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What is diagnostic bias?
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| Diego Casali
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C for me, too.
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| kudo
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i go for B, diagnostic bias since initially they are all healthy men
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| robin082006
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After search some documents, I go with C
Example of lead-time bias
Disease 'A' is 100% fatal Disease 'A' lasts 7 years from onset to death Disease 'A' patients are asymptomatic for 4 years Disease 'A' median survival 3 years after diagnosis Screening Test can identify Disease 'A' early
Detection occurs 2 years before clinical diagnosis
Disease 'A' still lasts 7 years before death
Disease 'A' is now asymptomatic for 2 years
Disease 'A' median survival 5 years after diagnosis
Screening Test falsely appears to prolong survival
Screened and unscreened patients each survive 7 years S
SCreened patients know diagnosis 2 years earlier
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| Diego Casali
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Thank you, robin!
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| zubr
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c. Lead time bias
Research concluded that Blood test increased survival compared to Rectal exam.
A test cannot increase survival. An earlier diagnostic and treatment can.
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