NONMEM Users Network Archive

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Re: Missing value when modeling categorical data

From: wangx826
Date: 08 Oct 2009 12:04:28 -0500

Thanks, Dr. Holford. But if I set a MDV column to state the missing time
points for each subject, would my logistic model still work? --I mean,
without considering censoring. I want to know if this problem leads to a
big structural error in my model. This will help me see the hidden problem
in my previous model.

Thanks,
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 - 13:04:28 EDT

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