Describing Omega that includes both BSV and IOV

Dear all, Currently I’m summarizing the NONMEM estimates of population PK for writing a manuscript. However, I wonder how to describe the omega which includes both between-subject variability and inter-occasional variability. The code of ‘variability’ is followed below, $PK IF(OCC.EQ.1) IOV = ETA(8) IF(OCC.EQ.2) IOV = ETA(9) IF(OCC.EQ.3) IOV = ETA(10) …. KA = THETA(9) * EXP(IOV) (à In final model, PK parameter was estimated like this) ; KA = THETA(9) * EXP(ETA(4)+IOV) (à When I used this code, there were some problems (boundary error, large RSE (>80%), very small estimate of BSV and so on) ) ; KA = THETA(9) * EXP(ETA(4)) (à when I used BSV only, the OFV is quite higher than upper two cases, so I thought that IOV should be considered. ) $OMEGA BLOCK(1) SAME $OMEGA BLOCK(1) SAME $OMEGA BLOCK(1) 0.3 In this case, the individual eta was re-calculated in one subject according to occasion, isn’t it? Then, how should I describe this ‘variability’ and estimate of omega in a manuscript? (i.e., between subject variability containing inter-occasional variability? Or any other appropriate term?) I will appreciate if someone give any advice. Thanks in advance. Best regards, SoJeong Yi SoJeong Yi, Ph.D Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea Tel: 82-2-740-8291 Fax: 82-2-742-9252 C.P: 82-10-3178-4133 E-mail: <mailto:[email protected]> [email protected]