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Timing of electronic reminders did not improve trial participant questionnaire response: a randomized trial and meta-analyses

Partha Sarathy, Prasanna; Kottam, Lucksy; Mitchell, Alex; Parker, Adwoa; Brealey, Stephen; Coleman, Elizabeth; Northgraves, Matthew; Torgerson, David; Rangan, Amar; Keding, Ada


Prasanna Partha Sarathy

Lucksy Kottam

Alex Mitchell

Adwoa Parker

Stephen Brealey

Elizabeth Coleman

David Torgerson

Amar Rangan

Ada Keding


Objectives: The objective of this study was to assess whether timing of short messaging service (SMS) reminders improved postal questionnaire return rates from participants in a randomized controlled trial (RCT). Study Design and Setting: A Study Within A Trial (SWAT) embedded in a multicenter RCT evaluating three treatments for the frozen shoulder. Participants who provided a mobile telephone number were randomized to either prenotification SMS on the day of the questionnaire mail-out or postnotification SMS 4 days after questionnaire mail-out for the 3-month follow-up. The primary outcome was the proportion of participants who returned a valid questionnaire. A systematic review was undertaken to identify other embedded trials to perform a meta-analysis. Results: Of the 269 participants, 122/135 (90.4%) returned a valid questionnaire in the prenotification arm and 119/134 (88.8%) in the postnotification arm (difference of −1.6%; 95% CI of difference: −8.9%, 5.7%). There was no difference in time to response (HR = 1.04; 95% CI: 0.80 to 1.34) or need for additional reminders (OR = 0.71; 95% CI: 0.43 to 1.17). Meta-analysis of two RCTs showed no difference in response rates between prenotification and postnotification reminders (OR = 0.78 95% CI: 0.42 to 1.45). Conclusion: Timing of SMS reminders did not improve response rates and time to response or affect the need for additional reminders.


Partha Sarathy, P., Kottam, L., Mitchell, A., Parker, A., Brealey, S., Coleman, E., …Keding, A. (2020). Timing of electronic reminders did not improve trial participant questionnaire response: a randomized trial and meta-analyses. Journal of clinical epidemiology, 122, 70-77.

Journal Article Type Article
Acceptance Date Mar 3, 2020
Online Publication Date Mar 6, 2020
Publication Date Jun 1, 2020
Deposit Date Mar 9, 2020
Publicly Available Date Mar 7, 2021
Journal Journal of Clinical Epidemiology
Print ISSN 0895-4356
Electronic ISSN 1878-5921
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 122
Pages 70-77
Keywords Epidemiology; Randomized controlled trial; SMS; Text message; Retention; Study within a trial; Meta-analyses
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