Effects of a Tailored Text Messaging Intervention Among Diverse Adults With Type 2 Diabetes: Evidence From the 15-Month REACH Randomized Controlled Trial

OBJECTIVE Text messaging interventions have high potential for scalability and for reductions in health disparities. However, more rigorous, long-term trials are needed. We examined the long-term efficacy and mechanisms of a tailored text messaging intervention. RESEARCH DESIGN AND METHODS Adults with type 2 diabetes participated in a parallel-groups, 15-month randomized controlled trial and were assigned to receive Rapid Education/Encouragement and Communications for Health (REACH) for 12 months or control. REACH included interactive texts and tailored texts addressing medication adherence and nontailored texts supporting other self-care behaviors. Outcomes included hemoglobin A(1c) (HbA(1c)), diabetes medication adherence, self-care, and self-efficacy. RESULTS Participants (N = 506) were approximately half racial/ethnic minorities, and half were underinsured, had annual household incomes = 8.5% (69 mmol/mol). Half were prescribed insulin. Retention was over 90%. Median response rate to interactive texts was 91% (interquartile range 75%, 97%). The treatment effect on HbA(1c) at 6 months (-0.31%; 95% CI -0.61%, -0.02%) was greater among those with baseline HbA(1c) >= 8.5% (-0.74%; 95% CI -1.26%, -0.23%), and there was no evidence of effect modification by race/ethnicity or socioeconomic disadvantage. REACH improved medication adherence and diet through 12 months and self-efficacy through 6 months. Treatment effects were not significant for any outcome at 15 months. REACH reduced barriers to adherence, but barrier reduction did not mediate outcome improvements. CONCLUSIONS REACH engaged at-risk patients in diabetes self-management and improved short-term HbA(1c). More than texts alone may be needed to sustain the effects.