Table 2.

Technical feasibility of the electronic adherence monitor.

Issue	Comments
Device malfunction	3 (2%) out of 63 devices malfunctioned and were replaced: one of the devices was damaged by the participant, while the remaining had technical faults.
Data loss	191.6 (3%, 191.6/8365) of data were lost because of technical issues with the adherence monitors.
Device battery changes	Although all study participants had a solar charger and 13 had electric chargers, study staff completed 22 battery changes because of (1) poor mobile network that resulted in repeated attempts to transmit the data, which depleted the battery before its anticipated charging time; and/or (2) inability or failure of the participants to charge the batteries as requested.
Lost to follow-up	One participant was lost to follow-up because of a nonfunctioning phone number.
Change of phone numbers	Five participants changed their phone numbers
SMSa reminders not sent	44 (1%) of SMS reminders were not sent because of technical challenges such as poor network coverage
Number of messages sent unnecessarily	1935 (36%) SMS reminders were sent unnecessarily. In these cases, the electronic adherence monitor was opened to take medication, but poor mobile network coverage resulted in a delay or absence of the signals.

^aSMS: short message service.