Studies to inform the methods for Cochrane systematic reviews of diagnostic accuracy in stroke medicine
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Date
05/07/2011Author
Brazzelli, Miriam
Metadata
Abstract
BACKGROUND:
A variety of tests are used in clinical practice to help the diagnostic process and so
improve patient care. Many aspects of stroke management depend on accurate and
rapid diagnosis. Brain imaging, including CT or MRI, is necessary to identify the
location and extent of the cerebral lesion, and to determine the pathological type of
stroke and its likely cause. Current treatments - such as thrombolysis - for ischaemic
stroke have increased the need for clear evidence on which imaging test is optimal
for diagnosis in the acute phase of stroke.
Systematic reviews of diagnostic test accuracy may provide evidence on the best use
of a diagnostic test in clinical practice and help clinicians to decide among alternative
tests. The Cochrane Collaboration has recently included systematic reviews of
diagnostic test accuracy within its remit. However, to prepare Cochrane systematic
reviews of diagnostic test accuracy is challenging because the methods for such
reviews are still in a state of flux.
MATERIALS AND METHODS:
The research work undertaken for this thesis addresses four relevant methodological
aspects of such reviews and, I hope, will contribute to informing the development of
the methods for Cochrane systematic reviews of test accuracy:
i) I assessed the quality of reporting of imaging studies in stroke medicine
published between 1995 and 2008 with the current STAndards for the
Reporting of Diagnostic accuracy studies (STARD) criteria;
ii) I assessed the magnitude of publication bias in diagnostic accuracy
studies in stroke medicine, by reviewing all diagnostic abstracts presented
at two international stroke meetings between 1995 and 2004 and so
evaluating the characteristics and findings of the identified abstracts;
iii) I have evaluated the methods for preparing reviews of test accuracy by
undertaking a pilot review according to the draft recommendations of the
Cochrane Diagnostic Test Accuracy Working Group;
iv) I conducted a survey to assess a) how well clinicians and health
professionals interpret findings of Cochrane systematic reviews of
diagnostic accuracy presented in summary documents; and b) what is the
best format for summarising findings of Cochrane reviews of diagnostic
accuracy.
CONCLUSIONS:
In conclusion, methodological issues concerning the validity and reliability of
findings of studies included in systematic reviews of diagnostic accuracy remain of
fundamental importance. More empirical evidence is needed to address potential
biases such as reporting bias and publication bias. To allow dissemination of
diagnostic reviews findings in clinical practice better ways of communicating main
characteristics and key results of systematic reviews of diagnostic accuracy should be
considered. In the current literature, the quality of reporting and methodological quality of
imaging studies for the diagnosis of stroke is less than satisfactory and leaves room
for improvement. This is worrying, especially if current health imaging policies are
in fact based on poor quality evidence and hence scarce health resources may not
being deployed as effectively as they could be.