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Re: [NMusers] Markov model dataset

From: Ahmed Suleiman <a.a.s.a.suleiman_at_gmail.com>
Date: Mon, 8 Feb 2016 10:45:50 +0100

Hi Achim,

After some quick testing, and for some reason (which I am not aware of), if
a compartment (e.g. a PK compartment) is added before these adverse events
compartments, then it works fine. I would be also interested to know why.

Best regards,

Ahmed Suleiman

On Mon, Feb 8, 2016 at 8:22 AM, Achim Fritsch <a.fritsch_at_uni-bonn.de> wrote=
:

> Dear all,
>
>
>
> I am currently trying to model the transitions from CTCAE grade 0 - 3 (4
> states) for several
>
> toxicities using a markov approach in Nonmem.
>
> However, I am facing some problems with the data set, which I cannot solv=
e
> by myself.
>
>
>
> The set looks like this:
>
>
>
> C
>
> ID
>
> TIME
>
> DOSE
>
> DV
>
> EVID
>
> CMT
>
> AMT
>
> MDV
>
> 0
>
> 1
>
> 0
>
> 0
>
> 0
>
> 1
>
> 1
>
> 1
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 1
>
> 0
>
> 1
>
> 0
>
> 0
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> -1
>
> 0
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> -2
>
> 0
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> -3
>
> 0
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> -4
>
> 0
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 1
>
> 1
>
> 1
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> 2
>
> 0
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> 3
>
> 0
>
> 1
>
> 0
>
> 1
>
> 1
>
> 50
>
> 0
>
> 2
>
> 4
>
> 0
>
> 1
>
>
>
> To implement the markov property the compartments are emptied and
> initialized after each observation.
>
> When I try to execute the model I get the following error message for
> every record where the compartment without
>
> a previous observation is emptied :
>
>
>
> COMPARTMENT ASSOCIATED WITH THE PREDICTION IS OFF
>
>
>
> In the example above this error refers to record 4 - 6.
>
>
>
> When I remove these records the model works, but then I am violating the
> markovian assumption, if I am not mistaken.
>
>
>
> Am I missing something important? Any help is highly appreciated!
>
>
>
> Here are the relevant parts of the control file:
>
>
>
> $DES
>
>
>
> K01_F = K01 * EXP(-GAM*T) + DOSE*SLP
>
> K02_F = K02 * EXP(-GAM*T) + DOSE*SLP
>
> K03_F = K03 * EXP(-GAM*T) + DOSE*SLP
>
> K12_F = K12 * EXP(-GAM*T) + DOSE*SLP
>
> K23_F = K23 * EXP(-GAM*T) + DOSE*SLP
>
>
>
> KB10 = KB * EXP(-BA*DOSE)
>
> KB21 = KB * EXP(-BA*DOSE)
>
> KB32 = KB * EXP(-BA*DOSE)
>
> KB20 = KB * EXP(-BA*DOSE)
>
> KB30 = KB * EXP(-BA*DOSE)
>
>
>
> DADT(1) = A(2)*KB10 + A(3)*KB20 + A(4)*KB30 - A(1) * (K01_F + K02_F +
> K03_F) ; No grade
>
> DADT(2) = A(1)*K01_F - A(2) * (K12_F +
> KB10) ; Grade 1
>
> DADT(3) = A(2)*K12_F + A(1)*K02_F - A(3) * (K23_F + KB21 +
> KB20) ; Grade 2
>
> DADT(4) = A(3)*K23_F + A(1)*K03_F - A(4) * (KB32 + KB30)
> ; Grade 3
>
>
>
> $ERROR
>
>
>
> PB0 = A(1)
>
> PB1 = A(2)
>
> PB2 = A(3)
>
> PB3 = A(4)
>
>
>
> Y = 1
>
> IF(DV.EQ.1.AND.CMT.EQ.1) Y = A(1)
>
> IF(DV.EQ.1.AND.CMT.EQ.2) Y = A(2)
>
> IF(DV.EQ.1.AND.CMT.EQ.3) Y = A(3)
>
> IF(DV.EQ.1.AND.CMT.EQ.4) Y = A(4)
>
>
>
> $ESTIMATION SIG=3 MAXEVAL=9999 PRINT=1 METHOD=1 LAPLACIAN LIKE NO=
ABORT
>
>
>
>
>
>
>
> Thank you very much in advance!
>
>
>
> Kind regards
>
>
>
>
>
>
>
> ____________________
>
> *Achim Fritsch*
>
> Pharmacist
>
>
>
> Klinische Pharmazie
>
> Pharmazeutisches Institut
>
> Universit├Ąt Bonn
>
> An der Immenburg 4
>
> 53121 Bonn
>
>
>
> Tel.: 0228 / 73 5229
>
> Fax.: 0228 / 73 9757
>
>
>
> a.fritsch_at_uni-bonn.de
>
>
>
>
>

Received on Mon Feb 08 2016 - 04:45:50 EST

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