From: wangx826

Date: 08 Oct 2009 15:50:17 -0500

Dear Nick,

I think I didn't make it clear in my first email that my model is a PK-PD

linked model, which means, the probability of a certain event is a function

of drug exposure which can describe as a function of time and some other

parameters like CL, V, etc. But it seems to me that the hazard function

only takes time into account. I am not familiar with survival analysis so

this might be a very basic question: How can I combine the PK/PD model with

the time-to-event model?

Thanks in advance,

Tianli

On Oct 8 2009, Nick Holford wrote:

*>Tianli,
*

*>
*

*>Your data sounds like it could be described by a survival analysis. A
*

*>time to event model will give you the survivor function i.e. the prob of
*

*>not having had the event as a function of time. The event in your case
*

*>is defined by the 'certain PD score'. The censoring will of course be
*

*>taken care of by a typical survival analysis.
*

*>
*

*>Nick
*

*>
*

*>wangx826 *

*>> Dear NMUsers,
*

*>>
*

*>> I am modeling ordered-categorical PD data versus time, but since the
*

*>> clinical trial is ongoing, I don't currently have complete data set
*

*>> for each subject. In other words, for some subjects, I have 1 year's
*

*>> PD data, but for some others, I can only collect PD data for 1 month.
*

*>> For the 1 month's case, it is like missing data for the rest of time.
*

*>> But I need to consider time course of the proportion of subjects who
*

*>> got a certain PD score. In my case, if I use the general logistic
*

*>> regression model to fit the relationship between time and proportions
*

*>> of event, would there be any problem? If so, how can I avoid it? Or
*

*>> need I consider censoring like survival analysis?
*

*>>
*

*>> Any suggestion would be appreciated very much.
*

*>>
*

*>> Thanks in advance,
*

*>> Tianli
*

*>> *****************************************************************
*

*>> Tianli Wang
*

*>> University of Minnesota
*

*>
*

*>*

Received on Thu Oct 08 2009 - 16:50:17 EDT

Date: 08 Oct 2009 15:50:17 -0500

Dear Nick,

I think I didn't make it clear in my first email that my model is a PK-PD

linked model, which means, the probability of a certain event is a function

of drug exposure which can describe as a function of time and some other

parameters like CL, V, etc. But it seems to me that the hazard function

only takes time into account. I am not familiar with survival analysis so

this might be a very basic question: How can I combine the PK/PD model with

the time-to-event model?

Thanks in advance,

Tianli

On Oct 8 2009, Nick Holford wrote:

Received on Thu Oct 08 2009 - 16:50:17 EDT