Retention and Engagement of Rural Caregivers of Adolescents in a Short Message Service Intervention to Reduce Sugar-Sweetened Beverage Intake: An Exploratory Process Evaluation Study (Preprint)

BACKGROUND Rural caregivers and their adolescents consume excessive sugar-sweetened beverage (SSB) that increase their risk for health issues. Short message service (SMS) interventions show promise for changing health behaviors. Yet, engagement of rural populations in SMS interventions is understudied. This exploratory process evaluation study is part of a larger school-based trial targeting SSB intake in adolescents and their caregivers. OBJECTIVE The purpose is to describe caregiver retention and engagement in a six-month SMS strategy and explore differences by caregiver characteristics. METHODS Caregivers completed a baseline survey. Messages were sent up to two times per week and contained SSB intake assessments, educational information and infographics, and personalized strategies. In addition to retention, engagement indicators included assessment completion, total assessment completion reminders, total chosen strategies, and opened infographics. RESULTS Caregivers (n=357) were mostly between 35-44 years of age (52%), female (91%), White (95%), had an income >$50,000/year, had at least some college education (68%), and had high health literacy (86%). Average baseline SSB intake was 23.9 (SD=26.8) oz/day. Of those enrolled, 316 (89%) were retained. Caregivers with a greater income and education were retained at a higher rate (P<.05), yet no other demographic characteristic were related to retention. Among those retained, average engagement included: 4.1 (SD=1.3) of 5 assessments completed and with few reminders needed [4.1 (SD=3.7) out of 14 possible], 3.2 (SD=1.1) of 4 strategies selected, and 1.2 (SD=1.6) of 5 infographics opened. Several engagement indicators statistically varied by demographic characteristics, including 1) age: younger caregivers were less likely to complete assessments and older caregivers were more likely to click on an infographic 2) education: caregivers with a high school education or lower completed fewer assessments, and 3) health literacy: caregivers with lower health literacy completed fewer assessments and chose fewer strategies (all P <.05). Related to SSB, caregivers with a greater intention to change behaviors needed less reminders (P =.04). Also, higher baseline SSB intake were associated with lower engagement across all indicators except clicks on infographics (P <.05). CONCLUSIONS Overall, rural caregivers engaged with assessment messages at a relatively high rate, demonstrating the practicality of using SMS-based approaches in rural areas. Future research should develop targeted retention and engagement strategies for identified demographic subsets and examine how engagement influences changes in SSB intake. CLINICALTRIAL Clincialtrials.gov: NCT03740113