Bioequivalence and Bioavailability Forum

The smaller a study, the more uncertain its results [Study Assessment]

posted by Helmut – Vienna, Austria, 2014-07-08 19:39 (3809 d 16:28 ago) – Posting: # 13244
Views: 15,136

Hi,

❝ In the study, six subjects dropped out due to different reasons.

❝ Therefore, only 22 evaluable subjects were available for PK calculations and BE evaluation.

6/28 – that’s a lot! Which were the “different reasons”? How many subjects did complete each sequence? The latter information is only important if n₁ ≠ n₂ (imbalanced sequences).

❝ Whether this had resulted in higher Intrasubject variability and due to which the study may have failed?

Possible, but unlikely. With your remaining sample size the CVs and ratios should be pretty “stable”. To give you an impression we can calculate confidence limits of the CV. Let’s assume two cases: A CV of 28% obtained from 28 and 22 subjects; upper CL, α 0.2:

   n  CL of CV (%) 

 ──────────────────

  28     32.26     

  22     33.03

As expected the estimate from 28 subjects is more precise (lower upper CL), but the gain compared to 22 subjects is not dramatic.

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Helmut Schütz

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Complete thread:

Results Analysis unique_one 2014-07-08 08:58 [Study Assessment]
- Results Analysis ElMaestro 2014-07-08 10:08
  - Results Analysis unique_one 2014-07-08 10:42
    - Don’t hurry; explore consequences Helmut 2014-07-08 12:00
      - Don’t hurry; explore consequences unique_one 2014-07-08 14:01
        
        The smaller a study, the more uncertain its resultsHelmut 2014-07-08 17:39
        
        The smaller a study, the more uncertain its results unique_one 2014-07-09 06:59
        
        The smaller a study, the more uncertain its results unique_one 2014-07-10 07:09
    - 156 ? d_labes 2014-07-08 12:03
      - 156 ? unique_one 2014-07-08 14:03
    - Results Analysis Shuanghe 2014-07-08 12:57
      - Results Analysis unique_one 2014-07-08 14:08
        
        Results Analysis Samaya B 2014-07-09 07:58
        
        bootstrap Shuanghe 2014-07-09 18:26
        
        bootstrap Weidson 2021-07-03 01:36
        
        Bootstrapping BE: An attempt in 🇷 Helmut 2021-07-08 13:50
        
        Bootstrapping BE: An attempt in 🇷 ElMaestro 2021-07-09 14:15
        
        Bootstrapping BE: Desultory thoughts Helmut 2021-07-09 14:50
        
        Bootstrapping BE: Desultory thoughts ElMaestro 2021-07-09 16:29
        
        Bootstrapping BE: Desultory thoughts Helmut 2021-07-09 21:04
- Results Analysis Achievwin 2021-08-17 19:26

The smaller a study, the more un­cer­tain its results [Study As­sess­ment]

Complete thread:

The smaller a study, the more uncertain its results [Study Assessment]