NONMEM Users Network Archive

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RE: Time to event analysis using NONMEM

From: Serge Guzy <GUZY>
Date: Tue, 9 Jun 2009 09:36:36 -0700

I am not sure it will help but for time to event data I always used the
log-likelihood instead of the likelihood. This is usually done to
prevent truncation to zero (Like the default when using the normal
likelihood). Did you try?

Serge Guzy

President POP-PHARM

 

________________________________

From: owner-nmusers
On Behalf Of Anubha_Gupta
Sent: Tuesday, June 09, 2009 8:24 AM
To: nmusers
Subject: [NMusers] Time to event analysis using NONMEM

 

Dear NMUsers

I am trying to analyse time to single event data using NONMEM VI. I am
getting the following termination message. If some body could point out
what I am doing wrong or may be elaborate on the error message that
would be very helpful.

Thanks in advance

Anubha


0PROGRAM TERMINATED BY OBJ
ERROR IN CLIK WITH INDIVIDUAL 1 ID=0.40000000E+01
CONDITIONAL LIKELIHOOD FOR DATA FROM OBS RECORD 1
ESTIMATED TO BE NEGLIGIBLE
MESSAGE ISSUED FROM ESTIMATION STEP
AT INITIAL OBJ. FUNCTION EVALUATION


Data set



C

STUD

ID

TIME

CS

DOSE

.

101

4

111

0

0.4

.

101

5

51

0

0.4

.

101

6

31

0

0.8

C Missing DV

101

7

.

.

0.8

.

101

8

59

0

1.6

.

101

9

477

1

3.2

.

101

11

278

0

3.2

.

101

12

58

0

6.4

CS=1 is the censored event
TIME is in days


Model file:

$PROB Time To Event data

$INPUT C STUD ID TIME=DV CS DOSE

$DATA

IGNORE=C

$SUBR ADVAN=6 TOL=6
$MODEL COMP=(RISK)

$PK

BASE = THETA(1)*EXP(ETA(1)) ;the ETA is a placeholder here

$DES
DADT(1)=BASE ;hazard

$ERROR


HZ = A(1) ;hazard
SUR = EXP(-HZ) ;survival probability
DENS=HZ*SUR
Y = (1-CS)*DENS + CS*SUR

$THETA (0,.025) ; BASE
$OMEGA 0 FIX

$ESTIM MAXEVAL=9990 METHOD = COND LAPLACE LIKE PRINT=1 MSFO=msfb01
$COV PRINT=E



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Received on Tue Jun 09 2009 - 12:36:36 EDT

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