Effects of a tailored text messaging intervention among diverse adults with type 2 diabetes: Evidence from the 15-month REACH RCT

Objective: Text messaging interventions have high potential for scalability and to reduce 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 trial, assigned to receive REACH (Rapid Education/Encouragement and Communications for Health) for 12 months or control. REACH included interactive texts and tailored texts addressing medication adherence, and non-tailored texts supporting other self-care behaviors. Outcomes included HbA1c, diabetes medication adherence, self-care, and self-efficacy. Results: Participants (N=506) were approximately half racial/ethnic minority and half were underinsured, had annual household incomes <$35,000 USD and ≤ high school education; 11% were homeless. Average baseline HbA1c was 8.6%±1.8%; 70.0±19.7 mmol/mol) with n=219 having HbA1c≥8.5% (69 mmol/mol) and half were prescribed insulin. Retention was over 90%. Median response rate to interactive texts was 91% (interquartile range 75%, 97%). The treatment effect on HbA1c at 6 months (-0.31%; 95% CI [-0.61%, -0.02%]) was greater among those with baseline HbA1c≥8.5% (-0.74%; 95% CI [-1.26%, -0.23%]), and there was not 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 HbA1c. More than texts alone may be needed to sustain effects.