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Using re-randomisation designs to increase the efficiency and applicability of retention studies within trials: a
Beatriz Goulao1, Anne Duncan2, Karen Innes2
1Health Services Research Unit, University of Aberdeen, Aberdeen, Scotland. beatriz.goulao@abdn.ac.uk.
Trials
|April 29, 2023
Summary
The re-randomisation design enhances Studies within Trials (SWATs) by allowing multiple interventions and increasing participant numbers. This improves the validity and efficiency of clinical trial retention strategies.
Area of Science:
- Clinical Trials Methodology
- Health Services Research
Background:
- Poor participant retention in randomized trials compromises study validity.
- Studies Within Trials (SWATs) aim to optimize retention interventions.
- Current SWATs often assess interventions at single time points, limiting efficiency.
Purpose of the Study:
- To introduce and evaluate the re-randomisation design for SWATs.
- To demonstrate how this design can improve efficiency and generalisability.
- To address the limitation of single time-point assessments in traditional SWATs.
Main Methods:
- The re-randomisation design allows participants to be re-enrolled and re-randomised at multiple follow-up points.
- This design enables estimation of average effects across time points, increasing generalisability.
- A case study in a dental trial with two follow-up points illustrates the design's application.
Main Results:
- The case study involved a dental trial assessing the impact of a sticker on questionnaire response rates.
- The re-randomisation design potentially doubles the sample size compared to parallel arm trials.
- This increased sample size allows detection of smaller effect sizes, improving statistical power.
Conclusions:
- The re-randomisation design significantly enhances the efficiency and generalisability of SWATs.
- This approach is particularly beneficial for trials with multiple follow-up opportunities.
- It offers a more robust method for evaluating retention interventions in clinical research.
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