Missing values in elimination phase [NCA / SHAM]
Dear Pavan!
The statement about data mining in this post applies here also.
What do you mean by 'Inital Stage'?
Three values in the elimination phase simply are too many for imputation - at least according to my SOP.
Using AUCt for that subject would bias the T/R-ratio. It does not make sense to compare AUC16 of the test with AUC48 of the reference. One option would be to truncate AUCs at last time point you have data for both formulations in that subject. Intersubject CV will increase, but T/R should be unbiased.
Missing values in the absorption phase are even more tricky. You may keep the subject e.g., for gastric-resistant formulations (lag-times), if after the missing values you still have the absorption phase well-defined. If you see a 'first-time' Cmax I think you have to exclude the subject.
The statement about data mining in this post applies here also.
❝ Suppose we got 3 consecutive missing values in either Elimination Phase or
❝ Absorption Phase or At Initial Stage.
What do you mean by 'Inital Stage'?
❝ What is the action we need to take? ie to eliminate the subject from the
❝ analysis or to do analysis as it is.
Three values in the elimination phase simply are too many for imputation - at least according to my SOP.

Using AUCt for that subject would bias the T/R-ratio. It does not make sense to compare AUC16 of the test with AUC48 of the reference. One option would be to truncate AUCs at last time point you have data for both formulations in that subject. Intersubject CV will increase, but T/R should be unbiased.
Missing values in the absorption phase are even more tricky. You may keep the subject e.g., for gastric-resistant formulations (lag-times), if after the missing values you still have the absorption phase well-defined. If you see a 'first-time' Cmax I think you have to exclude the subject.
—
Dif-tor heh smusma 🖖🏼 Довге життя Україна!![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- Missing values in elimination phase NPavan 2009-05-22 15:07
- Missing values in elimination phaseHelmut 2009-05-22 16:52