Re: [Fwd: occasions during pregnancy]

----- Original Message ----- From: Kevin Dykstra [mailto:[email protected]] Sent: Tuesday, March 01, 2011 05:59 PM To: [email protected] <[email protected]>; 'nm nm' <[email protected]> Subject: RE: [NMusers] [Fwd: occasions during pregnancy] Paul, You might try plotting your etas 6-9 vs. trimester (coded at four levels) to ensure that the IOV is truly random by occasion, as your model assumes. Obviously, it is not unheard of that the IOV should be much larger than IIV, but I wouldn't start with that assumption. Usually there is at least some correlation within an individual. Good luck. Kevin Kevin Dykstra, PhD, FCP +1 978.655.1943 (O) +1 978.289.2987 (M) [email protected] | http://qPharmetra.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, March 01, 2011 10:53 AM To: nm nm Subject: [NMusers] [Fwd: occasions during pregnancy] ---------------------------- Original Message ---------------------------- Subject: occasions during pregnancy From: [email protected] Date: Tue, March 1, 2011 10:49 am To: "nm nm" <[email protected]> -------------------------------------------------------------------------- Hi all nmusers, I thank all who responded my questions yesterday. Almost all the responses suggested that several occasions of one patient should be put under one ID #. I re-code my control stream and adjusted the data file as following: $PK K12 = THETA(1)*EXP(ETA(1)) CL= THETA(2)*EXP(ETA(2)+ETA(6)*TRI1+ETA(7)*TRI2+ETA(8)*TRI3+ETA(9)*TRI4) $OMEGA .8; .1 .8; .1 .1 .8; .1 .1 .1 .8; .1 .1 .1 .1 .8; $OMEGA BLOCK(1) 0.9; $OMEGA BLOCK(1) SAME; $OMEGA BLOCK(1) SAME; $OMEGA BLOCK(1) SAME; where TRI1,TRI2,TRI3, and TRI4 are different stages of pregnancy. This model fits poorly for the data (from the plot of PRED, IPRED VS. DV), although the estimates are stable and reasonable. If I treat the different occasions as different patients, ignoring the correlation within the same patients, then the model fits quite well and the results are reasonable. I also noticed one note from Lewis Sheiner: Note that, as happens more often, at least with human data, than one might have thought, the IOV>IIV, then treating each occaasion as though it were a distinct individual is a reasonable approximation. --------------Date: Wed, 17 Nov 1999 13:57:18 -0800 From: Lewis Sheiner <[email protected]> Subject: Re: repeating cases--------- The parameters during pregnancy change quite large, so I am not sure if it is a reasonalble approximation to treat occasions as distinct individual, or I have to search the better models of putting those occasions under one ID? and what is the direction to improve the model? Any suggestion is greatly appreciated. Paul School of Pharmacy University of Pittsburgh 716 Salk Hall 3501 Terrace Street Pittsburgh, PA 15261 Phone: 412-648-8546 E-mail: [email protected] Yuanyue (Paul) Gao School of Pharmacy University of Pittsburgh 716 Salk Hall 3501 Terrace Street Pittsburgh, PA 15261 Phone: 412-648-8546 E-mail: [email protected] -------------------------------------------------------- UCB Pharma S.A. Allée de la Recherche, 60 1070 Brussels, Belgium Tel: +32.2.559.99.99 - Fax: +32.2.559.92.10 Registration number : RPM/RPR Brussels 0403.096.168 VAT BE 0403.096.168 - Bank 210-0045962-36 -------------------------------------------------------- Legal Notice: This electronic mail and its attachments are intended solely for the person(s) to whom they are addressed and contain information which is confidential or otherwise protected from disclosure, except for the purpose for which they are intended. Dissemination, distribution, or reproduction by anyone other than the intended recipients is prohibited and may be illegal. If you are not an intended recipient, please immediately inform the sender and return the electronic mail and its attachments and destroy any copies which may be in your possession. UCB screens electronic mails for viruses but does not warrant that this electronic mail is free of any viruses. UCB accepts no liability for any damage caused by any virus transmitted by this electronic mail. (Ref: #*UBP1208)