title: Quantifying Glaucoma Medication Adherence: The Relationship Between Self-Report, Electronic Monitoring, and Pharmacy Refill.
abstract: Glaucoma medications reduce the risk of progressive visual field loss, but adherence to these medications is often poor. A better understanding of the appropriate metrics for quantifying glaucoma medication adherence is needed. We describe and compare different means of quantifying glaucoma medication adherence.
  
  
  
  Adults with glaucoma were enrolled in a prospective 2-site study. Participants completed a self-report instrument and received electronic medication monitors to use for ∼3 months. Pharmacy records were queried regarding requested refills over the monitoring period; medication possession ratio (MPR) was calculated.
  
  
  
  Of the 137 total participants, those who answered "Very confident" to the question, "How confident are you that you always remember to use your glaucoma medications?" and "No" to the question, "In the past 4 weeks, did you ever forget to take your medicine?" were more likely [odds ratio (OR) 2.78, 95% confidence interval (CI) 1.19-6.52] to take ≥80% of the prescribed doses according to electronic medication monitors. Mean MPR was 1.49, standard deviation (SD) 0.82, range 0.1-5.31. The proportion of participants taking greater than or equal to 80% of the prescribed doses according to the electronic monitors was 59% for participants with MPR <1.2 (n = 27), 63% for participants with MPR 1.2-1.8 (n = 27), and 88% for MPR >1.8 (n = 25).
  
  
  
  Asking about confidence may be a good method of screening for poor adherence for glaucoma medication. MPR may be an inadequate representation of glaucoma medication adherence.
authors.affiliation: 1 Department of Ophthalmology, Duke University School of Medicine , Durham, North Carolina.
authors.forename: Jaya B
authors.initials: JB
authors.lastname: Kumar
authors.affiliation: 2 Department of Medicine, Durham VA Medical Center, Duke University School of Medicine , Durham, North Carolina.|3 Health Services Research & Development, Durham VA Medical Center , Durham, North Carolina.
authors.forename: Hayden B
authors.initials: HB
authors.lastname: Bosworth
authors.affiliation: 4 Eshelman School of Pharmacy, Pharmaceutical Outcomes and Policy, University of North Carolina Chapel Hill , North Carolina.
authors.forename: Betsy
authors.initials: B
authors.lastname: Sleath
authors.affiliation: 3 Health Services Research & Development, Durham VA Medical Center , Durham, North Carolina.
authors.forename: Sandra
authors.initials: S
authors.lastname: Woolson
authors.affiliation: 3 Health Services Research & Development, Durham VA Medical Center , Durham, North Carolina.|5 Department of Biostatistics and Bioinformatics, Duke University School of Medicine , Durham, North Carolina.
authors.forename: Maren
authors.initials: M
authors.lastname: Olsen
authors.affiliation: 3 Health Services Research & Development, Durham VA Medical Center , Durham, North Carolina.
authors.forename: Susanne
authors.initials: S
authors.lastname: Danus
authors.affiliation: 1 Department of Ophthalmology, Duke University School of Medicine , Durham, North Carolina.|3 Health Services Research & Development, Durham VA Medical Center , Durham, North Carolina.
authors.forename: Kelly W
authors.initials: KW
authors.lastname: Muir
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016903:Drug Monitoring; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D005901:Glaucoma / Q000188:drug therapy*; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D010593:Pharmaceutical Services / Q000706:statistics & numerical data*; D057566:Self Report