Effect of Text Messaging on Risk Factor Management in Patients With Coronary Heart Disease The CHAT Randomized Clinical Trial

BACKGROUND: Mobile health technologies are low cost, scalable interventions with the potential to promote patient engagement and behavior change. We aimed to test whether a culturally sensitive text messaging intervention supporting secondary prevention improves the control of risk factors in patients with coronary heart disease in China. METHODS AND RESULTS: In this multicenter, single-blinded randomized controlled trial, 822 patients (mean age, 56.4 [SD, 9.5] years; 14.1% women) with coronary heart disease and without diabetes mellitus from 37 hospitals in China were enrolled between August 2016 and March 2017. In addition to usual care, the control group (n=411) received 2 thank you messages/month; the intervention group (n=411) received 6 text messages/week for 6 months delivered by an automated computerized system. The messages provided educational and motivational information related to disease-specific knowledge, risk factor control, physical activity, and medication adherence. The primary end point was change in systolic blood pressure from baseline to 6 months. Secondary end points included the proportion with systolic blood pressure <140 mm Hg, smoking status, and change in body mass index, LDL-C (low-density lipoprotein cholesterol), and physical activity (assessed using the International Physical Activity Questionnaire). The end points were assessed using analyses of covariance. Follow-up was 99.6%. At 6 months, systolic blood pressure was not significantly lower in the intervention group compared with the control group, with a mean change (SD) of 3.2 (14.3) mm Hg and 2.0 (15.0) mm Hg (P>0.05) from baseline, respectively (mean net change, -1.3 mm Hg [95% CI, -3.3 to 0.8]; P=0.221). There were no significant differences in the change in LDL-C level, physical activity, body mass index, or smoking status between the 2 groups. Nearly all patients in the intervention group reported the text messages to be useful (96.1%), easy to understand (98.8%), appropriate in frequency (93.8%), and reported being willing to receive future text messages (94.8%). CONCLUSIONS: Text messages supporting secondary prevention among patients with coronary heart disease did not lead to a greater reduction in blood pressure at 6 months. Mobile phone text messaging for secondary prevention was feasible and highly acceptable to patients.