Defining time to concentration threshold [General Statistics]
Hi,
I am planning a study where I want to include the time until a pre-defined plasma concentration threshold is reached as a PK parameter. Two options/methods for defining this parameter has been discussed:
A) The simplest approach would be to use the first sampling time-point where the concentration exceeds the threshold.
B) The other approach would be to use linear interpolation to find a more precise estimate of the time the concentration actually crosses the threshold.
From a methodological point of view, I find option B somewhat more appealing, as this would give a more "correct" result. However, there are a few arguments making me lean more towards option A anyhow, including:
1. Option A requires no imputation/assumptions of plasma levels between samples.
2. Data based on actual sampling times will be analogous to Tmax and perhaps more recognizable/acceptable by the authorities.
3. I also plan to present the percentage of subjects exceeding the threshold value at each sampling timepoint. A definition according to option A would better correspond with this analysis.
-Is there a "standard" approach?
-Does anyone have any advice on the best approach or experience regarding regulatory acceptability of data?
Thanks,
/Martin
I am planning a study where I want to include the time until a pre-defined plasma concentration threshold is reached as a PK parameter. Two options/methods for defining this parameter has been discussed:
A) The simplest approach would be to use the first sampling time-point where the concentration exceeds the threshold.
B) The other approach would be to use linear interpolation to find a more precise estimate of the time the concentration actually crosses the threshold.
From a methodological point of view, I find option B somewhat more appealing, as this would give a more "correct" result. However, there are a few arguments making me lean more towards option A anyhow, including:
1. Option A requires no imputation/assumptions of plasma levels between samples.
2. Data based on actual sampling times will be analogous to Tmax and perhaps more recognizable/acceptable by the authorities.
3. I also plan to present the percentage of subjects exceeding the threshold value at each sampling timepoint. A definition according to option A would better correspond with this analysis.
-Is there a "standard" approach?
-Does anyone have any advice on the best approach or experience regarding regulatory acceptability of data?
Thanks,
/Martin
Complete thread:
- Defining time to concentration thresholdCytokrom C 2022-04-29 16:24 [General Statistics]
- Defining time to concentration threshold ElMaestro 2022-04-29 17:49
- I prefer interpolation Helmut 2022-04-29 19:03
- I prefer interpolation Cytokrom C 2022-05-01 22:44
- Continuous variable → mean Helmut 2022-05-02 00:05
- I prefer interpolation Cytokrom C 2022-05-01 22:44