Background: Poor medication adherence contributes to inadequate control of hypertension. However, the value of adherence monitoring is unknown.
Objective: To evaluate the impact of monitoring adherence with electronic pill bottles or bidirectional text messaging on improving hypertension control.
Design: Three-arm pragmatic randomized controlled trial.
Patients: One hundred forty-nine primary care patients aged 18-75 with hypertension and text messaging capabilities who were seen at least twice in the prior 12 months with at least two out-of-range blood pressure (BP) measurements, including the most recent visit.
Interventions: Patients were randomized in a 1:2:2 ratio to receive (1) usual care, (2) electronic pill bottles for medication adherence monitoring (pill bottle), and (3) bidirectional text messaging for medication adherence monitoring (bidirectional text).
Main measures: Change in systolic BP during the final 4-month visit compared with baseline.
Key results: At the 4-month follow-up visit, mean (SD) change values in systolic blood pressure were - 4.7 (23.4) mmHg in usual care, - 4.3 (21.5) mmHg in the pill bottle arm, and - 4.6 (19.8) mmHg in the text arm. There was no significant change in systolic blood pressure between control and the pill bottle arm (p = 0.94) or the text messaging arm (p = 1.00), and the two intervention arms did not differ from each other (p = 0.93).
Conclusions: Despite good measured adherence, neither feedback with electronic pill bottles nor bidirectional text messaging about medication adherence improved blood pressure control. Adherence to prescribed medications was not improved enough to affect BP control or it was not the primary driver of poor control.
Trial registration: clinicaltrials.gov (NCT02778542).
Keywords: health behavior; hypertension; medication adherence; primary care.