Randomised evaluation of pre-notification of trial participants before self-report outcome data collection to improve retention: SWAT86

Sutton, CJ; Cotterill, S; Forshaw, D; Rhodes, S; Haig, A; Hammond, A

Abstract

Background
Retention is considered the second highest trial methods priority in the UK after recruitment. There is limited evidence on whether notifying trial participants that a follow-up questionnaire will be sent soon (‘pre-notification’) affects retention.

Methods
This Study Within a Trial (SWAT) evaluated whether sending a pre-notification letter or email around 2 weeks before sending a self-report questionnaire increased retention, in terms of provision of the host trial primary outcome. The SWAT was a randomised, two-arm, parallel-design (1:1 allocation ratio) trial, controlled by ‘no pre-notification letter’. It was embedded within the WORKWELL host trial, which evaluated the impact of job retention vocational rehabilitation on work-related and health-related outcomes of employed people with inflammatory arthritis. The SWAT primary outcome was a valid response for the WORKWELL primary outcome.

Results
Two hundred forty-four trial participants took part in the SWAT. All were included in the analysis. Among those sent a pre-reminder, 100/121 (83%) provided a valid response for the WORKWELL primary outcome, compared to 97/123 (79%) of those not sent a pre-reminder. The estimated adjusted odds ratio was 1.28 (95% confidence interval 0.67–2.42), with a risk difference of 3.8% (95% CI -6.1 to 13.6%), favouring the prereminder. The estimated intervention cost per additional participant retained was £53.42, and the total cost per additional participant retained was £46.52.

Conclusion
Researchers may have a small improvement in trial retention by using pre-notification. The cost per additional participant retained is relatively low. However, further evaluations are merited.

Citation

Sutton, C., Cotterill, S., Forshaw, D., Rhodes, S., Haig, A., & Hammond, A. (2022). Randomised evaluation of pre-notification of trial participants before self-report outcome data collection to improve retention: SWAT86. Research Methods in Medicine & Health Sciences, 3(4), 107-115. https://doi.org/10.1177/26320843221098427

• Journal Article Type: Article
• Online Publication Date: May 7, 2022
• Publication Date: May 7, 2022
• Deposit Date: May 12, 2022
• Publicly Available Date: May 12, 2022
• Journal: Research Methods in Medicine & Health Sciences
• Print ISSN: 2632-0843
• Electronic ISSN: 2632-0843
• Publisher: SAGE Publications
• Volume: 3
• Issue: 4
• Pages: 107-115
• DOI: https://doi.org/10.1177/26320843221098427
• Keywords: study within a trial, data management in clinical trials, alternative trial design and implementation issues, trial methodology, pre-notification, retention, trial conduct
• Publisher URL: https://journals.sagepub.com/doi/10.1177/17589983211060620
• Additional Information: Projects : PROMETHEUS: SWAT 86