Table 1.

Methods for monitoring medication adherence and their drawbacks

Method	Drawbacks
Patient report	Unreliable (forgetting, hiding)
Patient self-assessment questionnaire	Unreliable (forgetting, hiding)
Patient diary	Unreliable (forgetting, hiding)
Informant report/questionnaire	Unreliable (lack of information, opinion)
Pill count	Somewhat unreliable, pills may not have been ingested
Clinical response/adverse effects	Unreliable, as presence/absence of efficacy and adverse effects is multiply determined
Assessment of physiologic response	Unreliable, as physiologic response is multiply determined
Blister pack	Somewhat unreliable, pills may not have been ingested
MEMS cap	Somewhat unreliable, pills may not have been ingested
Electronic pill trays	Somewhat unreliable, pills may not have been ingested
Pharmacy/prescription refill record	Somewhat unreliable, pills may not have been ingested
Observed ingestion	Highly resource intensive, can lead to conflicts
Measurement of drug in bodily fluid or blood	Only cross-sectional; improved adherence preceding a clinic visit (“white coat compliance”)
Measurement of biomarker	Only cross-sectional; requites additive
Hair analysis	Requires long hair, requires a lot of strands, special lab needed
Ingestible event marker/digital health feedback system	Requires accepting a microelectronic chip in the pill and wearing a receiver on a patch on the torso; to date still expensive and not widely available

MEMS – medication event monitoring system