User preferences for and engagement with text messages to support antihypertensive medication adherence: Findings from a pilot study evaluating an emergency department-based behavioral intervention.

Objective: We examined users' preferences for and engagement with text messages delivered as part of an emergency department (ED)-based intervention to improve antihypertensive medication adherence.
Methods: We recruited ED patients with elevated blood pressure for a pilot randomized trial evaluating a medication adherence intervention with text messages. Intervention participants chose text content and frequency, received texts for 45 days, and completed a feedback survey. We defined engagement via responses to texts. We examined participant characteristics associated with text preferences, engagement, and feedback.
Results: Participants (N = 101) were 57% female and 46% non-White. Most participants (71%) chose to receive both reminder and informational texts; 94% chose reminder texts once per day and 97% chose informational texts three times per week. Median text message response rate was 56% (IQR 26-80%). Participants who were Black (p < 0.01), had lower income (p = 0.03), or had lower medication adherence (p < 0.01) rated the program as more helpful and wanted additional functionalities for adherence support.
Conclusions and Practice Implications: While overall engagement was modest, participants at risk of worse health outcomes expressed more value and interest in the program. Findings inform the design of text messaging interventions for antihypertensive medication adherence and support targeting vulnerable patients to reduce health disparities.
Clinical Trials Registration: NCT02672787.
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