From:"Prins, N.H. (Klaas)"   
Subject:[NMusers] EVID data item and beyond  
Date:Fri, March 8, 2002 10:20 am  

Dear nm-users,

Currently I am working on a study that consisted of 4 different study parts
in which several dosing schemes were tested, i.e. 3 schemes of multiple
dosing and 1 of continuous infusion. Initially, I created separate data sets
for each study part and inserted intermediate time points to get smooth
curves when plotting observed and predicted versus time. Using either the
MDV (0=observation, 1=missing) or EVID (0=observation, 1=dosing,
2=other/simulation) data item, I managed to get decent fits for each study
part. Also combining data from different study parts resulted in succesful
NM runs. 

However, I did not feel satisfied with making more than one dataset and a
couple of control streams. Therefore, I set out to put together a single
dataset containing data of all study parts. Then, the aim was to flag out
the study parts that did not need to be evaluated in specific run, by
setting EVID to 2 (other event). In this manner, I created 6 different
evaluation schemes and listed them in data items EV1 to EV6. For instance,
scheme EV4 was created to evaluate study parts 1 and 4 only, then all
records for those parts were set to 0, 1 and 2 (see above) and all other
records were set to 2 (flagged as 'other'). 
The $INPUT control stream read the following:
$INPUT ID TIME AMT RATE DV SEX WT PART EV1=DROP EV2=DROP EV3=DROP EV4=EVID
EV5=DROP EV6=DROP
So, by toggling on and off the EVx=EVID/DROP, I hoped to get my desired
evaluation. 

It did not work since the nm-tran reported for the data records of study
parts that were flagged out:
THE DV DATA ITEM IS POSITIVE, BUT THE MDV DATA ITEM IS 1
I did not specify a MDV data item, so this must refer to a 'generated MDV'.
I do understand this, since for these parts, the observations are read and
NM is suprised that it is asked to consider this as a simulation record.
Now, after this exhausting problem description, could somebody comment on
this issue and provide hints on how to surpass this? Any suggestion is much
appreciated.

Thanks in advance and have a nice weekend,
Klaas Prins
Drug Metabolism & Kinetics
- Pharmacokinetics Section
RH 2143
N.V. Organon
PO Box 20
5340 BH  Oss
The Netherlands
tel: +31 412 663884
fax: +31 412 662542
klaas.prins@organon.com


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> The $INPUT control stream read the following:
> $INPUT ID TIME AMT RATE DV SEX WT PART EV1=DROP EV2=DROP EV3=DROP EV4=EVID
> EV5=DROP EV6=DROP
> So, by toggling on and off the EVx=EVID/DROP, I hoped to get my desired
> evaluation. 

> It did not work since the nm-tran reported for the data records of study
> parts that were flagged out:
> THE DV DATA ITEM IS POSITIVE, BUT THE MDV DATA ITEM IS 1
> I did not specify a MDV data item, so this must refer to a 'generated MDV'.

When I have seen this it is a WARNING not an ERROR.  NM-TRAN generates the warning
but NONMEM should still be able to run and will ignore these records. 

You can turn off WARNINGS with this record:
$WARNINGS NONE
if the warning messages interfere with your enjoyment of running NONMEM.

You do pay a price by making NONMEM do extra work moving useless data around but
that is up to you. I would personally prefer to create sub-sets of data from the one
you have that contain just the records you need. I typically do tens or hundreds of
runs on a single data set so dont see the point of having the extra data overhead.

Nick

-- 
Nick Holford, Divn Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand
email:n.holford@auckland.ac.nz tel:+64(9)373-7599x6730 fax:373-7556
http://www.health.auckland.ac.nz/pharmacology/staff/nholford/