Here is an example that might work as an example of not clinically
meaningful but statistically significant
J Clin Epidemiol. Author manuscript; available in PMC 2012 Jun 1.
Published in final edited form as:
J Clin Epidemiol. 2011 Jun; 64(6): 583593.
Published online 2010 Dec 16. doi: 10.1016/j.jclinepi.2010.09.007
PMCID: PMC3079810
NIHMSID: NIHMS243539
Optimism bias leads to inconclusive results - an empirical study
Benjamin Djulbegovic,1,2 Ambuj Kumar,1,2 Anja Magazin,2 Anneke T.
Schroen,4 Heloisa Soares,5 Iztok Hozo,6 Mike Clarke,7 Daniel Sargent,8 and
Michael J. Schell2
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Clin Epidemiol
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Abstract
Objective
Optimism bias refers to unwarranted belief in the efficacy of new
therapies. We assessed the impact of optimism bias on a proportion of
trials that did not answer their research question successfully, and
explored whether poor accrual or optimism bias is responsible for
inconclusive results.
Study Design
Systematic review
Setting
Retrospective analysis of a consecutive series phase III randomized
controlled trials (RCTs) performed under the aegis of National Cancer
Institute Cooperative groups.
Results
359 trials (374 comparisons) enrolling 150,232 patients were analyzed. 70%
(262/374) of the trials generated conclusive results according to the
statistical criteria. Investigators made definitive statements related to
the treatment preference in 73% (273/374) of studies. Investigators
judgments and statistical inferences were concordant in 75% (279/374) of
trials. Investigators consistently overestimated their expected treatment
effects, but to a significantly larger extent for inconclusive trials. The
median ratio of expected over observed hazard ratio or odds ratio was 1.34
(range 0.19 15.40) in conclusive trials compared to 1.86 (range 1.09
12.00) in inconclusive studies (p<0.0001). Only 17% of the trials had
treatment effects that matched original researchers expectations.
Conclusion
Formal statistical inference is sufficient to answer the research question
in 75% of RCTs. The answers to the other 25% depend mostly on subjective
judgments, which at times are in conflict with statistical inference.
Optimism bias significantly contributes to inconclusive results.
Keywords: optimism-bias, inconclusive trials, randomized controlled
trials, bias, study design, systematic review
Key finding
Optimism bias refers to unwarranted belief in the efficacy of new
therapies, and significantly contributes to inconclusive results. Formal
statistical inference alone is not sufficient to answer the research
question. The answers to the research question also depend on subjective
judgments, which at times are in conflict with statistical inference.
What this adds to what was known
How often and why results from randomized clinical trials are
inconclusive, and whether there is a concordance between statistical
inferences and investigators global judgments in phase III randomized
controlled trials is not known. This is the first empirical study to show
the reasons for inconclusive findings.
.
snip
.
Found at this web address
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079810/
I hope that this helps
.
.
Sincerely,
David Dillard
Temple University
(215) 204 - 4584
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On Fri, 16 Sep 2016, Cristian Baicus wrote:
> The effect on cognition of the treatment in Alzheimer disease (compared to clinically minimal importance).
> Agree with the others concerning treatment in COPD on QoL (St George scale, where the effect=minimal important
> effect, but when you substract the effect of placebo the effect is lesser).
>
> dr. Cristian Baicuswww.baicus.ro
>
> from my iPad
>
> On 16 sept. 2016, at 11:48 a.m., Andy Hutchinson <[log in to unmask]> wrote:
>
> Hello, I wonder if someone can help me with an example for teaching purposes
>
>
>
> I’m looking for a good example of a published study that found a statistically significant
> difference in a patient-oriented outcome (i.e. not a surrogate outcome such as BP, HbA1c or LDL-C)
> that was not clinically meaningful. Ideally something to do with drug therapy rather than non-drug
> treatment
>
>
>
> I have an example quoted of an NSAID producing a difference in mean time to walk 50 feet on people
> with OA of 0.7 seconds, p<0.001, but I have no idea where that came from.
>
>
>
> I’m sure someone on this illustrious group will have a pet example or two!
>
>
>
> Thanks very much
>
>
>
> Andy
>
>
>
> Andy Hutchinson
>
> Medicines Education Technical Adviser
>
> Medicines and Prescribing Programme
> National Institute for Health and Care Excellence
>
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>
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