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Education And Debate

Evidence based diagnostics

BMJ 2005; 330 doi: (Published 24 March 2005) Cite this as: BMJ 2005;330:724

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Authors' reply

Setting sail for the sea of diagnostic research

EDITOR—A number of people have shown a very kind interest in our article on the architecture of evidence based diagnostic research. We are greatly thankful for that.

Gasko is right in pointing out that phase I of diagnostic research is very important. By underlining the following phases II to IV, we aimed at getting the ‘key’ into the lock and open the door to evidence based diagnostics. This is the point Öhman and Giocoli may have missed. To us it is not a question about getting significantly more positive results, but of getting results that are significantly more meaningful to patients.

We agree with Kilpatrick, that widespread introduction of diagnostic interventions that do more good than harm may be facilitated through NICE or its equivalent. However, diagnostic trials should not become a safe haven from EU directives. Diagnostic trials should be conducted with the same rigor as therapeutic trials. We do find that it is high time to improve the quality of all trials irrespective of topic (1,2,3).

Ter Riet and coworkers refer to literature on phased approaches to diagnostic research. We agree that the approaches have been too loosely connected to evidence based diagnostics. We think one can only learn about the improvement of clinical outcomes by studying the clinical course of patients. Therefore we need randomised clinical trials, even though they may get large and difficult to handle.

Moayyeri and Soltani correctly point out that more development is needed. Not only new tests, but also traditional tests including signs, symptoms, or clinical scores certainly need evaluation.

Sanderson and coworkers rightly argue that genetic tests should not be seen as something special. When pointing out that some diagnostic tests may be self evident, e.g. the confirmatory test for trisomy 21 in a person with Down's syndrome, we may have oversimplified matters unnecessarily in our article.

Christian Gluud
Lise Lotte Gluud

Cochrane Hepato-Biliary Group, Copenhagen Trial Unit, Centre for Clinical Intervention Research, H:S Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark

1. Kjaergard LL, Villumsen J, Gluud C. Reported methodological quality and discrepancies between large and small randomized trials in meta-analyses. Ann Intern Med 2001;135:982-989.

2. Kjaergard LL, Frederiksen S, Gluud C. Validity of randomized clinical trials in GASTROENTEROLOGY from 1964-2000. Gastroenterology 2002;122:1157-1160.

3. Kjaergard LL, Gluud C. Funding, disease area, and internal validity of hepato-biliary randomized clinical trials. Am J Gastroenterol 2002;97:2708-2713.

Competing interests: None declared

Competing interests: No competing interests

24 May 2005
Christian Gluud
head of department
Lise Lotte Gluud
H:S Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark