[R] Repeated measures cummulative logit mixed model

[David Winsemius]

On Aug 16, 2011, at 6:36 AM, Jim Trabas wrote:

> Dear R help gurus,
>
>
> I have the following problem and I would be delighted if you could  
> help me.
>
>> From a large (1500) cohort of patients we have been taking some  
>> measurements
> (ECG measurements, but its not important). The measurements are  
> ordinal in 4
> grades (Grade I-IV, grade IV being the most severe form). Every  
> patients has
> been measured several times (usually once per year). The follow-ups  
> are
> different for each patient (ranging from days to several years),  
> thus some
> patients have only 1 measurement and some have several. A patient  
> can shift
> from Grade to Grade, that is a patient can be measured now as Grade  
> I and
> later as Grade II and then at then next measurement he can return to  
> Grade
> I.

This should probably be followed up on the mixed models SIG list.

(Using Baron's RSiteSearch page.)

Search results with : repeated "proportional odds logistic"

http://finzi.psych.upenn.edu/R/library/repolr/html/00Index.html
http://finzi.psych.upenn.edu/R/Rhelp02/archive/99576.html

Search results with: repeated "ordered logit"

http://finzi.psych.upenn.edu/R/library/ordinal/doc/primer.pdf

That last one has citations to Agresti articles, which means it may  
have useful termininogy to be used in searching the very informative  
Thompson/Agresti compendium of R methods:

https://home.comcast.net/~lthompson221/Splusdiscrete2.pdf

The mixed-models SIG would seem to be a natural place to look and for  
that I use the advanced search panel fpr google to construct this  
search of its archives:

http://www.google.com/search?hl=en&lr=&q=repeated+logit+site%3Ahttps%3A%2F%2Fstat.ethz.ch%2Fpipermail%2Fr-sig-mixed-models

(I did trim some of the trailing bits that seemsed superfluous.)

-- 
David.

> My data are in the following format
>
> Patient ID, Time of Measurement, Grade
>
> I would like to model the probability of being in each of the Grades  
> (I-V)
> as a function of time. I guess i require a repeated measure  
> cumulative logit
> mixed model with random slope and intercept (for each patient).
>
> Could anyone pin point me at any information that would help me  
> accomplish
> this in R? Packages? Books?
>
> Information about categorical data analysis with R seems to be poor  
> in the
> Internet.
>
> Thank you very much on advance
> JT
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Repeated-measures-cummulative-logit-mixed-model-tp3746845p3746845.html
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>
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David Winsemius, MD
West Hartford, CT