Accuracy of Patient-reported Adherence to Glaucoma Medications on a Visual Analog Scale Compared With Electronic Monitors

• Type of Material: Article
• Authors: Robyn Sayner, University of North Carolina at Chapel Hill; Delesha M. Carpenter, University of North Carolina at Chapel Hill; Susan J. Blalock, University of North Carolina at Chapel Hill; Alan L. Robin, University of Maryland; Kelly W. Muir, Duke University; Mary Elizabeth Hartnett, University of Utah; Annette Giangiacomo, Emory University; Gail Tudor, Husson University; Betsy Sleath, University of North Carolina at Chapel Hill
• Language: English
• Date: 2015-09-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2015 Elsevier HS Journals, Inc.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.clinthera.2015.06.008
• Title of Journal or Parent Work: Clinical Therapeutics
• ISSN: 0149-2918
• Volume: 37
• Issue: 9
• Start Page: 1975
• End Page: 1985
• Grant/Funding Information: This project was supported by grant EY018400 (PI: Betsy Sleath) from the National Eye Institute and by grant UL 1RR02574 7 (PI: Betsy Sleath) from the National Center of Research Resources, NIH.
• Keywords: electronically monitored medication adherence; PERSISTENCE; self-reported medication; THERAPY; PATTERNS; OPEN-ANGLE GLAUCOMA; Life Sciences & Biomedicine; adherence; Pharmacology & Pharmacy; glaucoma; PHARMACY CLAIMS DATA; OCULAR HYPERTENSION; DETERMINANTS; NONADHERENCE; PREVALENCE
• Research Categories: Health Sciences, Opthamology; Health Sciences, Pharmacology

Abstract

Purpose: Glaucoma medications can reduce intraocular pressure and improve clinical outcomes when patients adhere to their medication regimen. Providers often ask glaucoma patients to self-report their adherence, but the accuracy of this self-report method has received little scientific attention. Our purpose was to compare a self-report medication adherence measure with adherence data collected from Medication Event Monitoring Systems (MEMS) electronic monitors. Additionally, we sought to identify which patient characteristics were associated with over-reporting adherence on the self-reported measure. Methods: English-speaking adult glaucoma patients were recruited for this observational cohort study from six ophthalmology practices. Patients were interviewed immediately after a baseline medical visit and were given MEMS containers, which were used to record adherence over a 60-day period. MEMS data were used to calculate percent adherence, which measured the percentage of the prescribed number of doses taken, and timing adherence, which assessed the percent doses taken on time. Patients self-reported adherence to their glaucoma medications on a visual analog scale (VAS) approximately 60 days following the baseline visit. Bivariate analyses and logistic regressions were used to analyze the data. Self-reported medication adherence on the VAS was plotted against MEMS adherence to illustrate the level of discrepancy between self-reported and electronically-monitored adherence. Findings: The analyses included 240 patients who returned their MEMS containers and who self-reported medication adherence at the 60-day follow-up visit. When compared with MEMS-measured percent adherence, 31% of patients (n=75) over-estimated their adherence on the VAS. When compared with MEMS-measured timing adherence, 74% (n=177) of patients over-estimated their adherence on the VAS. For the MEMS-measured percent adherence, logistic regression revealed that patients who were newly prescribed glaucoma medications were significantly more likely to over-report adherence on the VAS (OR=3.07, 95% CI: 1.22, 7.75). For the MEMS–measured timing adherence, being male (chi-square=6.78, p=0.009) and being prescribed glaucoma medications dosed multiple times daily (chi-square =4.02, p=0.045) were significantly associated with patients over-reporting adherence on the VAS. However, only male gender remained a significant predictor of over-reporting adherence in the logistic regression, (OR=4.05, 95% CI: 1.73, 9.47). Implications: Many glaucoma patients, especially new patients, over-estimated their medication adherence. Because patients were likely to over-report percent doses taken and timing adherence, providers may want to ask patients additional questions about when they take their glaucoma medications in order to potentially detect issues with taking glaucoma medications on time.