[How can we evaluate medication adherence? What are the methods?]

Abstract

Introduction: Identifying the difficulties of the patient towards following his medication regimen remains complex for the healthcare provider. This can be explained by the multidimensional character of medication adherence and, actually, the evaluation of this phenomenon. The objective of this work was to review the various methods to measure medication adherence.

Methods: We performed a search on PubMed completed by a manual one.

Results: Two types of measure are described. The "direct" methods are based on the measurement of the level of medicine or metabolite in blood or urine, measurement of biologic markers in blood or measurement of physiologic or clinical markers. The "indirect" methods are represented by the analysis of the administrative databases (prescription, rate of prescription refills); pill counts; electronic medication monitors; the self-reported measures by the patient or his close relations (questionnaires, diaries, interviews); the opinion of the healthcare provider.

Discussion: None of these tools supplants the others, each having limits either of feasibility, or reliability. In the end, it is the crossing of the information stemming from these various equipments that allows an idea on the adherence behavior of the patient and especially, dimensions on which he is most in trouble.

Conclusion: The identification of these difficulties can allow the healthcare provider to develop behavioral and organizational skills tailored to the patient follow-up.