Cox Model – How to Report AUC in Cox Regression?

auccox-model

I need to calculate the AUC for a Cox regression model. SAS is giving me a time dependent AUC as below. How do I report this for the paper?

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Best Answer

What's routinely done with Cox survival models is to report the concordance or C-index. That's the fraction of comparable cases for which the predicted and observed order of event times agrees. In a binary regression model that type of index would be the AUC. See this page for example. It's possible that, in an abuse of terminology, someone asked you for AUC when the request was intended to be for a C-index.

For the time-dependent AUC you could simply show the plot itself if there's space, or report selected time points in the text and put the plot into supplemental material. It would be important also to show confidence intervals around the AUC estimates. Do make sure that you understand which method has been used to calculate the time-dependent AUC, as there are several.

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