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Would really appreciate some advice on using MatLab Simbiology for Population PK modelling!

Basically, when I try to fit parameters using the population fit (NLME) method, I encounter an error/warning message "Covariate 'Potassium' has no valid value for group id '33'". I'm guessing this is because I have a missing value for Potassium levels (a covariate) in subject 33.

In fact, I have missing data for several covariates for several subjects!

I'm really greenhorn at using MatLab's SimBio so would appreciate detailed advice in simple terms on how to churn out a Population PK model if there's missing values. Thanks:)

Nicholas Syn
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1 Answers1

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The MATLAB/SimBiology implementation of NLME does not support missing values for covariates. You need to exclude from the estimation any individuals that do not have covariate data. If you are using the SimBiology Desktop, there are a couple of easy ways to exclude these individuals from your data. First, you can select the rows, right click on them, and select "Exclude selected rows from data". You can also create an exclusion rule as follows:

  • Clicking on the "Explore Data" tab in the toolstrip
  • Click on the button in the toolstrip labeled "Edit Exclusions"
  • Add a new exclusion with the expression "isnan(Potassium)"
  • Make sure both "Evaluate" and "Exclude Rows" are checked
agoldsipe
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