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
Trial Snapshot
- Phase
- Not Applicable
- Sponsor
- Enrollment
- 250
- Locations
- 1
- Primary Endpoint
- proportion of reported sample size definitions
Study Overview
Brief Summary
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.
Detailed Description
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.
Study Design
- Study Type
- Observational
- Time Perspective
- Prospective
Eligibility Criteria
- Sex
- All
- Accepts Healthy Volunteers
- No
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
Outcomes
Primary Outcomes
proportion of reported sample size definitions
Time Frame: up to three months after retrievement and inclusion of all studies
number of included studies with explicit sample size definition/ number of included studies
Secondary Outcomes
No secondary outcomes reported
Investigators
Agostino Colli
Head of Internal Medicine Department AO provincia di Lecco
Azienda Ospedaliera di Lecco