Methods for evaluation of medication adherence and persistence using automated databases

UMMS Affiliation

Meyers Primary Care Institute

Publication Date


Document Type



*Databases, Factual; Drug Prescriptions; Drug Therapy; Humans; *Patient Compliance; Pharmacies; Pharmacoepidemiology


Health Services Research | Primary Care


PURPOSE: Our aim was to perform a systematic review of the methods currently being used to assess adherence and persistence in pharmacoepidemiological and pharmacoeconomic studies using automated databases.

METHODS: A MEDLINE search of English language literature was performed to identify studies published between January 1, 1980 and March 31, 2004 that evaluated adherence, compliance, persistence, switching, or discontinuations of medications using automated dispensing data (pharmacy records). Two study investigators independently reviewed the abstracts and articles to determine relevant studies according to specified criteria.

RESULTS: A total of 136 articles met the criteria for evaluation. The types of measures of adherence and persistence commonly reported include the medication possession ratio and related measures of medication availability (77 studies), discontinuation/continuation (58 studies), switching (34 studies), medication gaps (13 studies), refill compliance (7 studies), and retentiveness/turbulence (4 studies). Specific issues considered include the assessment of exposed time to drug therapy and specification of the follow-up period.

CONCLUSIONS: The terminology, definitions, and methods to determine adherence and persistence differ greatly in the published literature. The appropriateness and choice of the specific measure employed should be determined by the overall goals of the study, as well as the relative advantages and limitations of the measures.

DOI of Published Version



Pharmacoepidemiol Drug Saf. 2006 Aug;15(8):565-74; discussion 575-7. Link to article on publisher's site

Journal/Book/Conference Title

Pharmacoepidemiology and drug safety

Related Resources

Link to Article in PubMed

PubMed ID