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Re: SEED status with SAEM method

From: hai le ba <lebahai01>
Date: Thu, 5 Nov 2020 11:58:58 +0100

Sorry, I've copied a wrong code of model.
The right is:
"$PK

MU_1= LOG(THETA(1))

KA=EXP(MU_1+ETA(1))

MU_2=LOG(THETA(2))+ THETA(4)*LOG(AGE/60.13)
CL= EXP(MU_2+ETA(2))

MU_3=LOG(THETA(3))+THETA(5)*LOG(WEI/66.49)
V=EXP(MU_3+ETA(3))

S2=V
IF (TIME.LT.12) TAD=TIME
IF (TIME.GE.12.AND.TIME.LT.24) TAD=TIME-12
IF (TIME.GE.12.AND.TIME.LT.36) TAD=TIME-24
IF (TIME.GE.36.AND.TIME.LT.48) TAD=TIME-36

$ERROR
EP1=EPS(1)
IPRED=F
IRES=DV-IPRED
W=F
IWRES=IRES/W
Y=IPRED+EPS(1)*W

Many thanks for your support!
Best regards,

Le jeu. 5 nov. 2020 à 11:15, hai le ba <lebahai01
rit :

> Dear Sir Jakob and Jeroen,
> Thanks for your reply.
> In fact, i've a one compartment model, with two levels of random effect
> (IIV, EPS) and covariate effect on CL, V.
> $PK
>
> MU_1= LOG(THETA(1))
>
> KA=EXP(MU_1+ETA(1))
>
> MU_2=LOG(THETA(2)+ THETA(4)*LOG(AGE/60.13))
> CL= EXP(MU_2+ETA(2))
>
> MU_3=LOG(THETA(3)+THETA(5)*LOG(WEI/66.49))
> V=EXP(MU_3+ETA(3))
>
> S2=V
> IF (TIME.LT.12) TAD=TIME
> IF (TIME.GE.12.AND.TIME.LT.24) TAD=TIME-12
> IF (TIME.GE.12.AND.TIME.LT.36) TAD=TIME-24
> IF (TIME.GE.36.AND.TIME.LT.48) TAD=TIME-36
>
> $ERROR
> EP1=EPS(1)
> IPRED=F
> IRES=DV-IPRED
> W=F
> IWRES=IRES/W
> Y=IPRED+EPS(1)*W
>
> I've used this model to simulate the complete database (10 000 IDs). From
> this database, the smaller dataset was randomly generated with respect to
> the rule of one PK sample per each ID. After that, I want to check how
> many IDs are necessary to get a good estimation for each method ( FOCEI,
> SAEM, BAYES, composite (ITS/SAEM/IMP/BAYES))?
>
> For FOCEI, I can't get convergence.
>
> For SAEM, I've got some troubles with the stability for EPS when I tried
> to change the SEED status?
> Otherwise, the good estimations were obtained with RSE (10-20%) for the
> other parameters.
>
>
> convergence for this setting of NBURN.
> "
> Convergence achieved
>
> STOCHASTIC PORTION WAS COMPLETED
> REDUCED STOCHASTIC PORTION WAS COMPLETED"
>
> Could you give me some instructions?
>
> Many thanks in advance for your responses.
> Best regards,
> Hai, LE Ba
> Ph.D Student
> La faculté de Pharmacie - Aix Marseille université
> Hanoi university of Pharmacy
> Email: lebahai01
> hailb
> bahai.le
>
>
> On Thu, Nov 5, 2020 at 10:43 AM Jakob Ribbing <
> jakob.ribbing
>
>> Dear LE Ba,
>>
>> You did not share much information on your model, except that you have
>> one observations per subject and that EPS (or rather sigma) is estimated=
 (I
>> assume then a continuous endpoint).
>> Is thisyour only level of random effect, so that you have no omega/eta
>> for IOV or IIV? With one observations per subject it will be difficult t=
o
>> find support for more than one level.
>> And for a model with only residual error (no IIV), would not the FO
>> Estimation method be sufficient, so why would you need to use SAEM for t=
his
>> data/model?
>>
>> Best regards
>>
>> Jakob
>>
>>
>>
>> Jakob Ribbing, Ph.D.
>>
>> Senior Consultant, Pharmetheus AB
>>
>>
>> Cell/Mobile: +46 (0)70 514 33 77
>>
>> Jakob.Ribbing
>>
>> www.pharmetheus.com
>>
>> Phone, Office: +46 (0)18 513 328
>>
>> Uppsala Science Park, Dag Hammarskjölds väg 36B
>> SE-752 37 Uppsala, Sweden
>>
>>
>>
>> This communication is confidential and is only intended for the use of
>> the individual or entity to which it is directed. It may contain
>> information that is privileged and exempt from disclosure under applicab=
le
>> law. If you are not the intended recipient please notify us immediately.
>> Please do not copy it or disclose its contents to any other person.
>>
>>
>>
>>
>> On 5 Nov 2020, at 09:41, hai le ba <lebahai01
>>
>> Hello nmusers,
>> I've tried to test the SAEM method on my dataset (1 sample for each ID)
>> with different SEED status. Sometimes, I've got good results (with RSE
>> <50%), but sometimes I can't get it.
>>
>> Example:
>> $EST METHOD=SAEM INTERACTION NBURN=3000 NITER=500 AUTO=1 PRINT=
=100
>> SEED=123456789
>> $EST METHOD=IMP EONLY=1 PRINT=1 NITER=5 ISAMPLE=1000 MAPITER=
=0
>> I've got EPS : 0.00064 (RSE=63%)
>>
>> but
>> $EST METHOD=SAEM INTERACTION NBURN=3000 NITER=500 AUTO=1 PRINT=
=100
>> SEED=123235489
>> $EST METHOD=IMP EONLY=1 PRINT=1 NITER=5 ISAMPLE=1000 MAPITER=
=0
>> I've got EPS : 0.0223 (RSE=18%)
>>
>> Could i trust on the good results (EPS=0.0223)? How can we control thi=
s
>> problem?
>>
>> Thank you very much,
>> Hai, LE Ba
>> Ph.D Student
>> La faculté de Pharmacie - Aix Marseille université
>> Hanoi university of Pharmacy
>> Email: lebahai01
>> hailb
>> bahai.le
>>
>>
>>

Received on Thu Nov 05 2020 - 05:58:58 EST

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