Bioequivalence and Bioavailability Forum

90% CIs for BE? [🇷 for BE/BA]

posted by Helmut  – Vienna, Austria, 2008-11-17 14:30 (6418 d 09:40 ago) – Posting: # 2688
Views: 15,884

Dear Yung-jin,

I agree with ElMaestro. BTW, Westlake’s CI should never be used and thrown into the statistical garbage collection because it obscures information about the location of the difference (I have not the slightest idea why it’s still used in WinNonlin).
Example from a study with low variability (CV_intra 8.63%, n=12):

Shortest CI:   100.54% – 113.52% (PE 106.84%)
Westlake’s CI:  88.06% – 111.94%

According to the original paper of Westlake* the CI would be stated as ±11.94%… You have no clue that the BA of the test formulation is statistically significant (though not clinically relevant) higher than the reference’s.

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• Westlake WJ. Symmetrical Confidence Intervals for Bioequivalence Trials. Biometrics. 1976;32(4):741–4. doi:10.2307/2529259.

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Dif-tor heh smusma 🖖🏼 Довге життя Україна! 
Helmut Schütz


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Complete thread:

• 90% CIs for BE? yjlee168 2008-11-17 08:52 
  • 90% CIs for BE? ElMaestro 2008-11-17 09:46
  • 90% CIs for BE? d_labes 2008-11-17 13:07
    • There can be only one! Helmut 2008-11-17 17:12
  • 90% CIs for BE?Helmut 2008-11-17 13:30
    • 90% CIs for BE? ElMaestro 2008-11-17 13:51
      • 90% CIs for BE? d_labes 2008-11-17 13:56
    • 90% CIs for BE? yjlee168 2008-11-17 18:10
      • 90% CIs for BE? Helmut 2008-11-17 18:14
        • 90% CIs for BE? yjlee168 2008-11-17 18:26
          • 90% CIs for BE? ElMaestro 2008-11-17 19:49