RE: covariates

From:"Renee Ying Hong" yinghong@pharm.usyd.edu.au Subject: RE: [NMusers] covariates Date: Thu, September 16, 2004 2:57 am Hello, Nick 1. My understanding of the allometric models you mentioned are as follows: CLi = CLstd * (WTi / WTstd) **0.75; Qi = Qstd * (WTi / WTstd)**0.75 V1i = V1std * (WTi / WT)**1; V2i = V2std * (WTi / WT)**1 each parameter/covariate combination will be run in NONMEM, and OFV will be compared with that of basic model. Since the subjects of my study are pediatric patients, WTstd would be 70 kg. Therefore, in my scenario, WTstd would be the media WT of the study patient cohort and (CL, Q, V)std would be the typical value of this study population. Please comment. 2. There are only 40 patients in this study. Therefore, in the second step, the stepwise/backward method will be employed to screen the other covariates? Kind Regards, Renee