RE: Time to event analysis using NONMEM
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
Quoted reply history
________________________________
From: [email protected] [mailto:[email protected]]
On Behalf Of [email protected]
Sent: Tuesday, June 09, 2009 8:24 AM
To: [email protected]
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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