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Evaluation of a holiday card retention strategy: a study within a trial (SWAT) embedded in a blood pressure reduction
Lesli E Skolarus1, Devin L Brown2, Ana Moraga3
1Davee Department of Neurology, Northwestern University, Chicago, USA. lesli.skolarus@northwestern.edu.
Insights
Sending a holiday card did not improve clinical trial participant retention in a low-resource emergency department setting. Further research into multicomponent interventions is needed to enhance participant follow-up completion.
Area of Science:
- Clinical Trials
- Health Services Research
- Patient Retention
Background:
- Participant retention is crucial for clinical trial validity and statistical power.
- Many retention strategies lack rigorous evaluation, especially in resource-constrained settings.
- This study evaluated a simple retention intervention in an emergency department setting.
Purpose of the Study:
- To assess if sending a holiday card improves follow-up completion rates in clinical trial participants.
- To evaluate the effectiveness of a low-cost retention strategy in a resource-limited emergency department.
- To determine if demographic factors modify the effect of holiday cards on retention.
Main Methods:
- A Study Within a Trial (SWAT) was embedded in a 2x2x2 randomized trial (Reach Out).
- Participants received standard retention strategies; one group additionally received a holiday card.
- The primary outcome was completion of the 6- or 12-month outcome assessment.
Main Results:
- Outcome assessment completion rates were similar between groups (54.5% with card vs. 58.4% without).
- The holiday card intervention showed no statistically significant difference in follow-up completion (p=0.43).
- No effect modification was observed based on age, sex, or race.
Conclusions:
- In this low-resource emergency department, holiday cards did not enhance clinical trial participant retention.
- Findings align with previous studies suggesting simple interventions may be insufficient.
- Multicomponent retention strategies and pragmatic evaluations are recommended for improving trial adherence.
Introduction:
Participant retention is essential to minimize bias, preserve statistical power, and strengthen the validity of clinical trial findings. Although retention strategies are widely used, many lack rigorous evaluation. We evaluated whether sending a holiday card, compared with usual follow-up procedure, improves follow-up completion among clinical trial participants recruited from a resource-constrained emergency department.
Methods:
We conducted a Study Within a Trial (SWAT) embedded within Reach Out, a 2 × 2 × 2 randomized trial of a mobile health-based behavioral intervention designed to reduce blood pressure among individuals with elevated blood pressure identified from a resource-constrained emergency department. All participants received standard retention strategies as part of the parent trial, with participants randomized to the SWAT intervention group additionally receiving a holiday card. The primary outcome was completion of the next available outcome assessment (6- or 12-month assessment). We estimated absolute differences with 95% confidence intervals in outcome assessment completion between participants who received a holiday card and those who did not, and then stratified by age, sex, and race.
Results:
Among Reach Out participants (N = 395), 198 were randomized to receive a holiday card and 197 to receive no card. Outcome assessment completion did not differ between participants who received a holiday card and those who did not (54.5% vs 58.4%; p = 0.43), and there was no evidence of effect modification by age, sex, or race.
Conclusion:
In this low-resource setting, receipt of a holiday card was not associated with higher outcome completion. These findings are consistent with prior studies and suggest that multicomponent interventions may be needed to increase retention, underscoring the value of pragmatic evaluations of retention interventions embedded within ongoing trials.
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