Predicting body weight as a function of gestational age

4 messages 4 people Latest: Nov 11, 2010

Predicting body weight as a function of gestational age

From: Brian Sadler Date: November 11, 2010 technical
Dear All, I am working on a PK model in neonates, infants, and children (postnatal ages 0-12 years). I am to the point of running simulations and was looking for a model to predict body weight as a function of gestational age. I could simply resample from the data used to construct the PK model or build a model based on the data in hand (n~200), but I was looking for a published model (based on a larger sample size) that might be used as a point of reference. As the relative difference between gestational age and postnatal age diminishes in older children models of body weight as a function of postnatal age for children >2 years old could also be useful. Thanks for any suggestions you might have. Cheers... Brian Brian M. Sadler, Ph.D. Sr Scientific Director ICON Development Solutions Internal Tel: 701-4860 External Tel: +1 (215) 616-4860 Mobile: +1 (919) 600-0889 Fax: +1 (215) 586-4048 Email: [email protected] Web: www.iconplc.com

RE: Predicting body weight as a function of gestational age

From: Liping Zhang Date: November 11, 2010 technical
Hi, Brian, I wonder why you want to model the body weight with age. Will the growth chart from CDC (based on children in US) or WHO (based on children in the world, and considering race), which contains statistics from a large pool and differentiated by gender be more helpful? for example, check http://www.cdc.gov/growthcharts/clinical_charts.htm#Summary. best regards, Liping
Quoted reply history
From: [email protected] [mailto:[email protected]] On Behalf Of Sadler, Brian Sent: Thursday, November 11, 2010 10:03 AM To: [email protected] Subject: [NMusers] Predicting body weight as a function of gestational age Dear All, I am working on a PK model in neonates, infants, and children (postnatal ages 0-12 years). I am to the point of running simulations and was looking for a model to predict body weight as a function of gestational age. I could simply resample from the data used to construct the PK model or build a model based on the data in hand (n~200), but I was looking for a published model (based on a larger sample size) that might be used as a point of reference. As the relative difference between gestational age and postnatal age diminishes in older children models of body weight as a function of postnatal age for children >2 years old could also be useful. Thanks for any suggestions you might have. Cheers... Brian Brian M. Sadler, Ph.D. Sr Scientific Director ICON Development Solutions Internal Tel: 701-4860 External Tel: +1 (215) 616-4860 Mobile: +1 (919) 600-0889 Fax: +1 (215) 586-4048 Email: [email protected] Web: www.iconplc.com [cid:[email protected]]

RE: Predicting body weight as a function of gestational age

From: Mahesh Samtani Date: November 11, 2010 technical
Hello, You can use the CDC growth charts that can be found here: http://www.cdc.gov/growthcharts/percentile_data_files.htm The interesting files from the website are: 1. WTAGEINF [XLS - 34 KB] http://www.cdc.gov/growthcharts/data/zscore/wtageinf.xls : birth to 36 months 2. WTAGE [XLS - 125 KB] http://www.cdc.gov/growthcharts/data/zscore/wtage.xls : 2 to 20 years I have struggled with the LMS parameter system in the CDC growth charts to simulate variability. I have used some approximations in the past. Does anyone have NONMEM code to simulate the variability in the weight age relationship using the LMS parameters [median (M), the generalized coefficient of variation (S), and the power in the Box-Cox transformation (L)]. Thank-you, Mahesh
Quoted reply history
From: [email protected] [mailto:[email protected]] On Behalf Of Sadler, Brian Sent: Thursday, November 11, 2010 10:03 AM To: [email protected] Subject: [NMusers] Predicting body weight as a function of gestational age Dear All, I am working on a PK model in neonates, infants, and children (postnatal ages 0-12 years). I am to the point of running simulations and was looking for a model to predict body weight as a function of gestational age. I could simply resample from the data used to construct the PK model or build a model based on the data in hand (n~200), but I was looking for a published model (based on a larger sample size) that might be used as a point of reference. As the relative difference between gestational age and postnatal age diminishes in older children models of body weight as a function of postnatal age for children >2 years old could also be useful. Thanks for any suggestions you might have. Cheers... Brian Brian M. Sadler, Ph.D. Sr Scientific Director ICON Development Solutions Internal Tel: 701-4860 External Tel: +1 (215) 616-4860 Mobile: +1 (919) 600-0889 Fax: +1 (215) 586-4048 Email: [email protected] Web: www.iconplc.com

RE: RE: Predicting body weight as a function of gestational age

From: Holly Kimko Date: November 11, 2010 technical
Hi: The updated Babson & Benda's growth chart for preterm babies (Fenton T., BMC Pediatrics, 2003, 3:13 - http://www.biomedcentral.com/1471-2431/3/13 will give you a part of the missing info - "preterm" babies. Best, Holly
Quoted reply history
From: [email protected] [mailto:[email protected]] On Behalf Of Sadler, Brian Sent: Thursday, November 11, 2010 10:35 AM To: [email protected] Subject: [NMusers] RE: Predicting body weight as a function of gestational age Thanks, Liping. The problem with the CDC and WHO data is that they are based on postnatal age (PNA). In my present model, gestational age (GA) was a better predictor of drug clearance and volume than PNA. Furthermore, body weight in the neonates appears to be better correlated with GA than PNA. Cheers... Brian From: Zhang, Liping (CD) [mailto:[email protected]] Sent: Thursday, November 11, 2010 10:23 AM To: Sadler, Brian; [email protected] Subject: RE: Predicting body weight as a function of gestational age Hi, Brian, I wonder why you want to model the body weight with age. Will the growth chart from CDC (based on children in US) or WHO (based on children in the world, and considering race), which contains statistics from a large pool and differentiated by gender be more helpful? for example, check http://www.cdc.gov/growthcharts/clinical_charts.htm#Summary. best regards, Liping From: [email protected] [mailto:[email protected]] On Behalf Of Sadler, Brian Sent: Thursday, November 11, 2010 10:03 AM To: [email protected] Subject: [NMusers] Predicting body weight as a function of gestational age Dear All, I am working on a PK model in neonates, infants, and children (postnatal ages 0-12 years). I am to the point of running simulations and was looking for a model to predict body weight as a function of gestational age. I could simply resample from the data used to construct the PK model or build a model based on the data in hand (n~200), but I was looking for a published model (based on a larger sample size) that might be used as a point of reference. As the relative difference between gestational age and postnatal age diminishes in older children models of body weight as a function of postnatal age for children >2 years old could also be useful. Thanks for any suggestions you might have. Cheers... Brian Brian M. Sadler, Ph.D. Sr Scientific Director ICON Development Solutions Internal Tel: 701-4860 External Tel: +1 (215) 616-4860 Mobile: +1 (919) 600-0889 Fax: +1 (215) 586-4048 Email: [email protected] Web: www.iconplc.com