Bioequivalence and Bioavailability Forum • Baseline correction examples

Baseline correction examples [Regulatives / Guidelines]

posted by BEQool – 2024-11-11 08:34 (179 d 17:01 ago) – Posting: # 24270
Views: 4,111

Hello all,

❝ Which mean? Though often applied I hope not the arithmetic one. The geometric would be better but what if at least of the values is BQL? I always use the median and never got any requests.

❝ BTW, be aware of softwares’ interpretation of non-numerics like "BQL". Example: 5.0, 7.0, "BQL"

Excel PHX/WNL R

❝ arithmetic mean 6.0 6.0 NA

❝ geometric mean 5.9 5.9 Error

❝ median 6.0 6.0 "7.0"

❝ Excel ignores the "BQL" and works with the numbers only. Same in PHX/WNL but we get the information that 2 values are used and 1 is missing. R essentially gives up.

why is geomteric mean not 0 if one of the values is 0 (or BLQ)? Are only positive values included in the calculation of geometric mean? I know that log(0) cannot be calculated but on the other hand value of 0 could be included in the calculation of geomean (equation: n-th root of the product of n values) and the geomean would be 0 regardless of other values.

We are currently studying an endogenous compound for which the endogenous baseline samples mostly below BLQ or slightly higher are expected. What is preferred for the time-averaged method in this case, to take the geometric mean or the median? In case the median is used, are BLQ values replaced with 0 not taken into account when calculating median as shown above (similar to geomean calculation)?

We were also wondering, if the pre dose sample at 0 h timepoint can be simultaneously considered as for detection of baseline concentration and also as the first PK sample? I would say that it can be used and the pro of this is that you dont have to take one more sample as well (in connection with the total volume of blood taken). On the other hand, one could argue that the same value will be taken into account twice; e.g. if we take the median for time-averaged method and this timepoint at 0h is the median, then baseline correction for the first pharmacokinetic sample would be 0 as the same value would be subtracted.

Regards
BEQool

Complete thread:

Baseline correction vs non-baseline correction jag009 2015-09-15 20:29 [Regulatives / Guidelines]
- Baseline correction vs non-baseline correction Lucas 2015-09-16 14:16
  - Baseline correction vs non-baseline correction Relaxation 2015-09-18 10:25
- Baseline correction or supra-therapeutic dose Helmut 2015-09-16 15:16
  - Baseline correction or supra-therapeutic dose Ohlbe 2015-09-16 17:55
    - Baseline profile prior to each period? Helmut 2015-09-16 18:15
    - Baseline correction examples Helmut 2015-09-17 15:44
      - Baseline correction examples Lucas 2015-09-18 14:19
        
        Baseline correction examples Helmut 2015-09-18 17:28
        
        Baseline correction examples Mauricio Sampaio 2016-02-07 03:05
        
        Baseline correction examples Lucas 2016-02-10 11:48
        
        Postmenopausal women Helmut 2016-02-10 12:26
        Baseline correction examples Mauricio Sampaio 2016-02-11 01:38
        Baseline correction examples Dr_Dan 2016-02-11 09:22
        
        Postmenopausal women Mauricio Sampaio 2016-02-12 03:24
        
        Postmenopausal women Dr_Dan 2016-02-15 17:45
        
        Baseline correction examplesBEQool 2024-11-11 07:34
        
        Baseline correction GeoMean and Median mittyri 2024-11-11 11:20
        
        Geometric mean? Helmut 2024-11-11 14:53
        
        Geometric mean? BEQool 2024-11-14 08:19
        
        Geometric mean ≈ MLE of median Helmut 2024-11-14 09:54
        
        Geometric mean ≈ MLE of median Mahmoud 2024-11-15 11:26
        
        Bias? Helmut 2024-11-16 08:43
        
        Bias? Mahmoud 2024-11-16 11:12
    - Baseline; another example Helmut 2015-09-18 17:16
      - Baseline; another example nobody 2016-02-12 09:10
        
        Baseline; another example Helmut 2016-02-12 13:37
        
        Baseline; another example nobody 2016-02-12 14:08
        
        Slowly going OT: BE study simulations Helmut 2016-02-12 15:47
        
        Slowly going OT: BE study simulations nobody 2016-02-12 16:15
        
        Religious debate Helmut 2016-02-12 17:04
        
        Religious debate nobody 2016-02-12 17:26
        
        Religious debate ElMaestro 2016-02-13 12:53
        
        Religious debate nobody 2016-02-14 15:23
        
        Slowly going OT: BE study simulations Ohlbe 2016-02-13 13:10
        
        Slowly going OT: BE study simulations Helmut 2016-02-13 15:02
        
        Slowly going OT: BE study simulations lizhao 2016-02-25 17:31
        
        Business as usual Helmut 2016-02-25 17:44
        
        Business as usual lizhao 2016-02-25 17:59