Health Communications Theory-Based Text Message Reminders Boost Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) Appointment Attendance Among American Indian Populations

<b>Background/Objectives:</b> The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) improves the health of nutritionally at-risk populations. However, engagement challenges, such as missed appointments and unredeemed food benefits, may limit program efficacy. Barriers to engagement are heightened among American Indian populations, who often experience disproportionately high levels of participation-related challenges. This study assessed whether newly developed health communication theory-based text messages incorporating persuasive language and different message framing (i.e., gain-framed and loss-framed) improved WIC appointment attendance and food benefit redemption rates, above and beyond standard information-based reminders. <b>Methods:</b> The sample included participants served by the Inter Tribal Council of Arizona WIC between the months of September 2022 and February 2023 who (a) had an appointment during the intervention period (n = 7584) or (b) were eligible to receive a reminder text about unused food benefits during the intervention period (n = 2177). A three-phase intervention design was used, with each phase lasting six weeks. During the baseline phase, participants received standard information-based text messages, while during the two intervention phases, participants received newly developed messages using (1) gain-framed and (2) loss-framed persuasive language. Difference-in-difference regression analyses compared whether differences in outcomes (i.e., appointment attendance and monthly food benefit redemption rates) between participants who received reminder messages and those who did not differed over intervention phases. <b>Results:</b> Receipt of both gain-framed and loss-framed theory-based messages was associated with higher appointment attendance, when compared to receipt of standard information-based messages during baseline (<i>p</i> = 0.003 and <i>p</i> = 0.01, respectively). Neither the gain-framed nor loss-framed messages were associated with higher food benefit redemption rates than standard messages. <b>Conclusions:</b> Results indicated that persuasive communication theory-based text reminders may be an effective, low-cost strategy to boost WIC appointment attendance among American Indians.