Dear Allstat,
We've created a simple prognostic index for sudden cardiac
death. Patients can score a minimum of 0 and a maximum of 11.
We've then classified patients into low or high risk based
on possible combinations of low/high score (i.e. low=0/high=1-11,
low=0-1/high=2-11, ..., low=0-10/high=11) and calculated
sensitivity and specificity at each of these points. We've then
produced a receiver operating characteristic (ROC) curve and
have calculated the area under the curve (AUC).
We are interesting in different types of death and it would
be useful to apply the same prognostic index to patients
who die of progressive heart failure and (hopefully) make a
statement that the prognostic index is significantly "better" for
sudden cardiac death (as it was designed) than for progressive
heart failure (in terms of AUC).
Does anyone have any suggestions of how we can go about this?
The standard error of the AUCs can be calculated and we could
obtain a measure of the standard error of the difference of the
AUCs, but this would result in a conservative test as cause of
death is probably not independent.
I am aware that there are references and methods available when
comparing two different indices with regard to the same cause of
death.
Thank-you in advance,
Mandy
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