I prefer "cross-sectional" for the reason that Paul highlighted (ie the time
frame issue). In a good diagnostic study the test result should be verified
with the reference standard ASAP. Any delay can lead to serious bias (we
have termed this "delayed verification bias" in one of our papers (i think
penny whiting in QUADAS has called this "disease progression bias" - but we
prefer our term as disease can progress or regress in the time interval from
test to reference standard)
See: Clark TJ, Ter Riet G, Coomarasamy A, Khan KS. Bias associated with
delayed verification in test accuracy studies: accuracy of tests for
endometrial hyperplasia may be much higher than we think! BMC Med. 2004 May
11;2(1):18. http://www.biomedcentral.com/content/pdf/1741-7015-2-18.pdf
in some situations, immediate verification is not possible, and patients
need to be followed clinically to detemine who had the disease and who did
not - i have seen this being called "delayed cross-sectional design" - maybe
the term "diagnostic cohort study" better describes this situation!
Arri
____________________________________________________________________________
____________
Arri Coomarasamy, MD, MRCOG
Specialist Registrar in Obstetrics and Gynaecology
Honorary Lecturer in Epidemiology
Birmingham Women's Hospital
Metchley Park Road
Edgbaston
Birmingham B15 2TG
United Kingdom
Tel 00 44 121 603 9800
Mobile (UK) 07956 498 457
See Course Website: www.acecourses.co.uk
____________________________________________________________________________
____________
-----Original Message-----
From: Evidence based health (EBH)
[mailto:[log in to unmask]]On Behalf Of Piersante
Sestini
Sent: 01 November 2004 18:50
To: [log in to unmask]
Subject: Re: Diagnostic test studies
At 10.41 01/11/2004 -0500, Doggett, David wrote:
> Really, "diagnostic study" is a class unto itself. It should not be
> encumbered with the stigma that"observational", "cross-sectional", or
> other non-RCT terms
I mostly agree with what you say, but just "diagnostic study" would be too
generic for my students to accept. They would argue that also a
case-control study could be used as a "diagnostic study".
Furthermore, "diagnostic study" here (and probably elsewhere) is sometimes
used as a synonymous for "diagnostic test", so it may be even more confusing
Paul Glasziou wrote:
>Though I like the name "diagnostic cohort" study, most other folk working
>in diagnostics are unhappy with the time frame it implies. So
>cross-sectional analytic study is the most accepted term for the
>reasonable design of taking a series of patients with the same presenting
>complaint and the applying some agreed gold standard to all cases.
What I don't understand is the meaning "analytic" here, as opposed to
"conventional" cross sectional studies. Laboratory and statistical analyses
are performed in both kinds of study. What am I missing?
thanks
Piersante Sestini
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