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Sample Size Definition in Cochrane Hepato-Biliary Trials

This study is currently recruiting participants.
Verified May 2012 by Azienda Ospedaliera di Lecco
Sponsor:
Information provided by (Responsible Party):
Agostino Colli, Azienda Ospedaliera di Lecco
ClinicalTrials.gov Identifier:
NCT01604720
First received: May 14, 2012
Last updated: November 15, 2012
Last verified: May 2012
History of Changes

May 14, 2012
November 15, 2012
July 2012
December 2012   (final data collection date for primary outcome measure)
proportion of reported sample size definitions [ Time Frame: up to three months after retrievement and inclusion of all studies ] [ Designated as safety issue: No ]
number of included studies with explicit sample size definition/ number of included studies
Same as current
Complete list of historical versions of study NCT01604720 on ClinicalTrials.gov Archive Site
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Sample Size Definition in Cochrane Hepato-Biliary Trials
Review: Analysis of the Sample Size Definitions in the Randomized Clinical Trials Included in Systematic Reviews of the Hepato-biliary Group of the Cochrane Collaboration

Sample size definition provides important information, allowing the groundwork for transparent reporting. The sample predefinition allows the trial to be large enough to be able to address the question that is being asked.

The aim of the present study is to assess, in all the randomized controlled trials (RCT) included in the Cochrane Hepato-Biliary Group (CHBG) systematic reviews, the quality of reporting sample size the accuracy of the calculations, the accuracy of the a priori assumptions and the effect on the agreement with pooled results in meta-analyses.

The investigators aim to answers to these questions

Questions

  • How large a proportion of recent hepato-biliary RCTs does report an adequate sample size estimation?
  • Primary outcome is clearly defined ? and clinical meaningful ?
  • Is the sample size calculation based on the primary outcome ?
  • Does the predicted control event rate coincide with the actual one?
  • What is the predicted intervention effect?
  • Are confidence intervals of primary outcome results reported? Is there evidence of difference between the two arms?
  • Is the effect size so large (> 50%) to suggest post hoc definition ?
  • What is the accepted error alpha and beta?
  • How many study do not comply with the usual rule of alpha = 5% beta = 20%?
  • Do trials with planned sample size do better than those without ? Is the overlap between CI results less frequent ? Are their results more frequently "statistical" significant ?
  • Do trials with planned sample more frequently agree with pooled results in meta-analysis ?
  • Has the protocol been published in a public register before inclusion of participant?
  • How often is intention-to-treat analyses employed as primary analysis?
  • How often is the trial results resting upon subgroup analysis?

Methods:

All the randomized clinical trials included in a systematic review of the Cochrane Hepato-biliary group (according to my search 272) were detected and retrieved. Only two arm, parallel group superiority randomised controlled trials with a single primary outcome.

The investigators excluded reports for which the study design was factorial, cluster, or crossover For all selected articles, the investigators systematically retrieved and assessed the full published report of the trial, any extra material or appendices available online, the study design article, if cited, and the details of online registration of the trial, if mentioned. A standardised data collection form was generated on the basis of a review of the literature and a priori discussion and tested by the research team.
Observational
Time Perspective: Prospective
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Non-Probability Sample

Randomized clinical trials included in systematic reviews of the hepato-biliary Group of the Cochrane Collaboration
Definition of Sample Size in Randomized Clinical Trial Assessing Liver Disease
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruiting
250
April 2013
December 2012   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Two arms, parallel group superiority randomised controlled trials with a single primary outcome,

Exclusion Criteria:

  • Reports for which the study design was factorial, cluster, or crossover
Both
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No
Contact: agostino colli, MD +390341489670 a.colli@ospedale.lecco.it
Contact: giovanni casazza, PhD +390250319653 giovanni.casazza@unimi.it
Italy
 
NCT01604720
AOLecco002
No
Agostino Colli, Azienda Ospedaliera di Lecco
Azienda Ospedaliera di Lecco
Not Provided
Principal Investigator: agostino colli, MD AO provincia di lecco
Azienda Ospedaliera di Lecco
May 2012

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP