Personal experiences of electronic measurement of medication adherence in elderly stroke survivors

Objective: The aim of this study was to examine the practicality and accuracy of using an electronic monitoring device as a means of measuring medication adherence in elderly stroke survivors, with emphasis on patients’ experiences. Methods: The Medication Event Monitoring System (MEMS), which records date and time of pill-bottle openings, was used to measure adherence to antihypertensive medication in a randomized controlled trial (RCT) of a brief psychological intervention with 58 stroke survivors. Patients were asked to describe and rate their experiences of using the MEMS pill bottle. Results: MEMS adherence was related to both pill count and self-reported adherence (Medication Adherence Report Scale). Most patients found the MEMS acceptable and easy to use, although some found it cumbersome and/or experienced difficulties with the cap. Nearly half (48 %) reported at least one instance where MEMS data did not reflect their pill-taking behavior (e.g. taking a tablet out the day before to take on a flight); 55 % of patients indicated that the MEMS helped them remember their medication, suggesting a mere measurement effect. Conclusion: Electronic pill monitoring has many flaws, including practical difficulties and data inaccuracies. There was evidence of a measurement effect, indicating that MEMS should be used in both intervention and control arms when used to measure adherence within RCTs. We also observed that the MEMS pill bottle is not suitable for measuring adherence in patients who use their own ‘days of the week’ box for sorting medication, as we found poorer adherence at follow-up in this group. Despite these limitations, we conclude that electronic monitoring presents the best method currently available for objective measurement of adherence, especially where detailed timing information is required. Accuracy may be improved by the concurrent use of other measures (e.g. pill count, self-report).