An Overview on the Medication Adherence Measures

Medication adherence is a crucial part of patient care and indispensable for reaching clinical goals.
The WHO reported that adherence among patients with chronic diseases averages only 50% in
developed countries. This is recognized as a significant public health issue, since medication nonadherence
leads to poor health outcomes and increased healthcare costs. Improving medication
adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve
medication adherence. One significant aspect of the strategies to improve medication adherence is to
understand its magnitude. However, there is a lack of general guidance for researchers and
healthcare professionals to choose the appropriate tools that can explore the extent of medication
adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This
article reviews both subjective and objective medication adherence measures, including direct
measures, those involving secondary database analysis, electronic medication packaging (EMP)
devices, pill count, clinician assessments and self-reports. Subjective measures generally provide
explanations for patient’s non-adherence whereas objective measures contribute to a more precise
record of patient’s medication-taking behavior. While choosing a suitable approach, researchers and
healthcare professionals should balance the reliability and practicality, especially cost effectiveness,
for their purpose. Meanwhile, because a perfect measure does not exist, a multi-measure approach
seems, currently, to be the best solution. This study should be able to provide a general direction for
professionals to choose the most suitable measures for their aims and subsequently deliver efficient,
tailored interventions to improve patient’s medication-taking behaviors.