Table 2.

Medicine Adherence Measurement Methods and Their Characteristics Reported in the Included Studies

Adherence Measurement Method	Self-Reported Adherence (MMAS and Its Related Scales) N=7	Refill Record-Based Adherence N=8	Prescription Abandonment N=1	Manual Pill Count N=1
Main Characteristics	Common in measuring adherence of antihypertensive drugs Simple and easy to be used Self-reporting style Subjected to overestimation of adherence level High chance of response bias	Common in measuring adherence of hyperlipidemia medications Common types: -Medication possession ratio (MPR) -The proportion of days covered (PDC) Quantitative measures Less subjected to overestimation of adherence level. Subjected to a possibility that medications being refilled – but not consumed properly.	Known as primary medication nonadherence Abandons to prescriptions portrayed that patients do not adhere to their medications Reasons for prescriptions abandon: low perceived benefit due to asymptomatic nature of the condition	More objective than self-reporting medication adherence Regarded as the gold standard for validating other methods It can be done without informing patients to avoid the disadvantage of pill dumping, where patients manipulate the number of pills.

Abbreviations: MMAS, Morisky Medication Adherence Scale; PDC, proportions of days covered; MPR, medication possession ratio.