Bioequivalence and Bioavailability Forum • ratio = difference of logs!

ratio = difference of logs! [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2013-03-11 02:17 (4229 d 11:36 ago) – Posting: # 10181
Views: 26,050

Dear Chirag,

❝ […] does this apply to the untransformed or Ln transformed data

❝

❝ The ratios were fine with the Ln transformed data.

Raw data! You need the ln-transformed data only in the BE-statistics. You would have to calculate the difference of logs and backtransform to get % covered. Example:

AUC_t 375, AUC_∞ 500, covered: 100×375/500=75%.
lnAUC_t 5.9269, lnAUC_∞ 6.2146, covered: 100×ℯ^{5.9269–6.2146}=75%.

A ratio of logs (95.37%) is nonsense.

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Helmut Schütz

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Complete thread:

AUCt not covering at least 80% of AUCinf ratnakar1811 2013-03-05 08:30 [Regulatives / Guidelines]
- AUCt not covering at least 80% of AUCinf d_labes 2013-03-05 11:12
  - AUCt not covering at least 80% of AUCinf ratnakar1811 2013-03-06 08:50
    - AUCt not covering at least 80% of AUCinf ElMaestro 2013-03-06 11:10
      - ADME-tox? Helmut 2013-03-06 14:35
        
        ADME-tox? ElMaestro 2013-03-06 16:40
        
        OT Helmut 2013-03-06 17:19
        
        OT ElMaestro 2013-03-07 17:19
        
        OT Helmut 2013-03-07 17:26
    - Science vs. regulations Helmut 2013-03-06 14:30
      - Science vs. regulations cakhatri 2013-03-10 08:59
        
        ratio = difference of logs!Helmut 2013-03-11 01:17
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      - Science vs. regulations qualityassurance 2020-04-23 14:11
        
        Science vs. regulations Helmut 2020-04-23 17:32
        
        Science vs. regulations Achievwin 2020-05-07 22:59
        
        Science vs. regulations Helmut 2020-05-07 23:54
    - AUCt not covering at least 80% of AUCinf Brus 2018-11-20 13:01
      - AUCt not covering at least 80% of AUCinf Astea 2020-06-05 19:05
        
        So what? Helmut 2020-06-06 12:02
        
        Carrot and whip Astea 2020-06-06 21:11
        
        Gedankenexperiment Helmut 2020-06-07 12:41
        
        Dead dogs mittyri 2020-06-07 20:32
        
        Aber meine Herren das ist keine physik Astea 2020-06-08 00:08
        
        Aber meine Dame, das ist alles Unsinn! Helmut 2020-06-08 01:04
        Bizarre paper Helmut 2020-06-08 12:43
        
        Bizarre paper ElMaestro 2020-06-08 15:33
        
        OT: Bias of AUCt, AUCall, pAUC Helmut 2020-06-08 15:53
        
        OT: Bias of AUCt, AUCall, pAUC ElMaestro 2020-06-09 08:45
        
        OT: Bias of AUCs; example Helmut 2020-06-09 14:07
        
        Maxwell's demon Astea 2020-06-12 14:15
        
        Dead dogs Helmut 2020-06-08 10:40