Personalized Patient Data and Behavioral Nudges to Improve Adherence to Chronic Cardiovascular Medications: A Randomized Pragmatic Trial

Abstract

Importance: Poor medication adherence is common. Text messaging is increasingly used to change patient behavior but often not rigorously tested.

Objective: To compare different types of text messaging strategies with usual care to improve medication refill adherence among patients nonadherent to cardiovascular medications.

Design, setting, and participants: Patient-level randomized pragmatic trial between October 2019 to April 2022 at 3 US health care systems, with last follow-up date of April 11, 2023. Adult (18 to <90 years) patients were eligible based on diagnosis of 1 or more cardiovascular condition(s) and prescribed medication to treat the condition. Patients who did not opt out and had a 7-day refill gap were randomized to 1 of 4 study groups.

Intervention(s): Generic text message refill reminders (generic reminder); behavioral nudge text refill reminders (behavioral nudge); behavioral nudge text refill reminders plus a fixed-message chatbot (behavioral nudge + chatbot); usual care.

Main outcomes and measures: Primary outcome was refill adherence based on pharmacy data using proportion of days covered at 12 months. Secondary outcomes were clinical events of emergency department visits, hospitalizations, and mortality.

Results: Among 9501 enrolled patients, baseline characteristics across the 4 groups were comparable (mean age, 60 years; 47% female [n = 4351]; 16% Black [n = 1517]; 49% Hispanic [n = 4564]). At 12 months, the mean proportion of days covered was 62.0% for generic reminder, 62.3% for behavioral nudge, 63.0% for behavioral nudge + chatbot, and 60.6% for usual care (P = .06). In adjusted analysis, when compared with usual care, mean proportion of days covered was 2.2 percentage points (95% CI, 0.3-4.2; P = .02) higher for generic reminder, 2.0 percentage points (95% CI, 0.1-3.9; P = .04) higher for behavioral nudge, and 2.3 percentage points (95%, 0.4-4.2; P = .02) higher for behavioral nudge + chatbot, none of which were statistically significant after multiple comparisons correction. There were no differences in clinical events between study groups.

Conclusions and relevance: Text message reminders targeting patients who delay refilling their cardiovascular medications did not improve medication adherence based on pharmacy refill data or reduce clinical events at 12 months. Poor medication adherence may be due to multiple factors. Future interventions may need to be designed to address the multiple factors influencing adherence.

Trial registration: ClinicalTrials.gov Identifier: NCT03973931.

Figure 1.. Patient Flow in a Study of Message Reminders to Improve Adherence to Chronic Cardiovascular Medications

^aStudy introductory letters were mailed to potentially eligible patients to provide information about the study as well as an opportunity to opt out if they chose not to participate. ^bRandomization was stratified by health care system and number of baseline medications and occurred in blocks of 4 patients within strata to ensure balance across study groups using an automated process.

Figure 2.. Proportion of Days Covered

A, Proportion of days covered was calculated using all medication classes identified as gapping at baseline. Patients actively receiving multiple study medications had all combinations of follow-up days for all baseline medications counted in the denominator; days that medications were filled were counted in the numerator. Results were then presented, aggregated by month following enrollment for the initial enrollment gaps and any subsequent gaps. B, Adjusted difference from usual care in proportion of days covered, stratified by follow-up month.

Figure 3.. Kaplan-Meier Rates for Secondary Clinical Outcomes Stratified by Treatment Group