Bioequivalence and Bioavailability Forum

Significant effects: Don’t worry, be happy! [General Sta­tis­tics]

posted by Helmut  – Vienna, Austria, 2020-12-22 16:27 (145 d 20:59 ago) – Posting: # 22154
Views: 688

Hi Moloko,

» Could somebody help me with my doubts about significant sequence/treatment/period
» effects in BE study?

Search the forum for sequence effect, treatment effect, and period effect. Lots of posts, references, etc. See also the articles about carryover and a significant treatment effect.

» My СI-s are within the range of 80.000% - 125.000%, so formally BE acceptance criterion is met.

Excellent. Open a bottle of champagne.

» But these p-values scare me...
»
» I don't have much experience in BE and I think it is not good then period or sequence factor influences PK-parameter.

• Unless the the study was extremely imbalanced (say, almost all subjects in one sequence and the rest in the other), period effects mean out, since both T and R are affected to the same extent. Nothing to worry about.
  
• Sequence effects (actually unequal carry-over) can not be “corrected” by a statistical method – only avoided by design (sufficiently long washout). It was shown in a large meta-analysis that in properly designed studies a significant effect is seen in ~ the level of the test and hence, likely is a statistical artifact (false positive). Forget it.
  
• Even a significant treatment effect is not important. Only the CI-inclusion counts.
  
• The fact that subjects differ is trivial. Only if you don’t see a significant effect you should start to worry (monozygotic twins or triplets in the study?) because it would violate the assumption of independence.

—
Dif-tor heh smusma 🖖
Helmut Schütz


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Complete thread:

• Significant effects Moloko 2020-12-22 11:41 [General Sta­tis­tics] 
  • Significant effects: Don’t worry, be happy!Helmut 2020-12-22 16:27
    • Significant effects: Don’t worry, be happy! Moloko 2020-12-23 13:24