GP text messages improve asthma and COPD medication adherence: a large-scale RCT

Non-adherence to prescribed treatment compromises outcomes in patients with both COPD and asthma. Text messages delivered through primary care may present an opportunity to improve adherence at scale. We aimed to explore whether a low-intensity supportive text message intervention that addresses both motivation and the ability to adhere could improve preventer inhaler medication adherence and symptom control. Patients with asthma and/or COPD prescribed a preventer inhaler were invited to take part by 89 GP practices in England in this individual-level randomised controlled trial. Supportive text reminders were compared against standard NHS care controls on the basis of self-reported adherence to medication and reported asthma and COPD control at baseline and at 13 and 26 weeks. A total of 5873 participants were randomised to the intervention (n=2929) and control (n=2944) groups. There was a 22.5% attrition rate for the treatment group compared with 0.2% in the control group, but the results were robust to several sensitivity checks that tested the impact of the differential attrition rate. The intervention resulted in small but statistically significant improvements in self-reported adherence in both the COPD and asthma cohorts of 0.10 and 0.16 points, respectively, in the MARS-5 scores at 26 weeks compared with those of the control group, with similar improvements observed at 13 weeks. A small but statistically significant improvement of 0.5 points on the ACT questionnaire was observed in terms of symptom control for asthma patients who received the intervention, although this improvement does not meet the commonly cited minimal clinically important difference (MCID) threshold of 3 points. No effect was observed on symptom control for COPD patients, and no differences were observed in prescription intervals or healthcare utilisation. We demonstrate that a simple and low-cost text message intervention, delivered via GP practices, can have a small but statistically significant effect on medication adherence in patients with asthma or COPD, with small improvements in symptom control for patients with asthma. Further work is needed to explore whether more comprehensive support, as recommended by NICE, can also be delivered at scale. ISRCTN10376144 ( https://doi.org/10.1186/ISRCTN10376144 ). Registered on 09/08/2022.