The Most Common Barriers to Glaucoma Medication Adherence: A Cross-Sectional Survey

Abstract

Purpose: To evaluate the frequency of 11 commonly cited barriers to optimal glaucoma medication adherence among glaucoma patients and to identify barriers contributing to poor adherence.

Design: Prospective, cross-sectional survey.

Participants: One hundred ninety adults with glaucoma taking 1 or more glaucoma medication who received care in glaucoma clinics in Ann Arbor, Michigan, and Baltimore, Maryland.

Methods: Participants completed a survey on demographic and disease characteristics, barriers to optimal glaucoma medication adherence, interest in an eye drop aid, and self-reported adherence (measured by the Morisky Adherence Scale). Descriptive statistics and logistic regression analyses were performed.

Main outcome measures: Frequency and number of barriers to adherence among both adherent and nonadherent patients. Odds ratios (ORs) with 95% confidence intervals (CIs) identifying barriers associated with poor adherence.

Results: Twenty-seven percent of the sample reported poor adherence. Sixty-one percent of all participants cited multiple barriers and 10% cited a single barrier as impediments to optimal adherence. Twenty-nine percent of subjects cited no barriers, although only 13% of patients who cited no barriers were nonadherent. Among nonadherent patients, 31% or more cited each of the 11 barriers as important. Logistic regression analysis, adjusted for age, revealed that the following barriers were associated with higher odds of nonadherence: decreased self-efficacy (OR, 4.7; 95% CI, 2.2-9.7; P ≤ 0.0001), difficulty instilling drops (OR, 2.3; 95% CI, 1.1-4.9; P = 0.03), forgetfulness (OR, 5.6; 95% CI, 2.6-12.1; P ≤ 0.0001), and difficulties with the medication schedule (OR, 2.9; 95% CI, 1.4-6.0; P = 0.006). For each additional barrier cited as important, there was a 10% increased odds of being nonadherent (OR, 1.1; 95% CI, 1.0-1.2; P = 0.01).

Conclusions: Each of the 11 barriers was important to at least 30% of surveyed patients with poor adherence, with most identifying multiple barriers to adherence. Low self-efficacy, forgetfulness, and difficulty with drop administration and the medication schedule were barriers associated with poor adherence. Interventions to improve medication adherence must address each patient's unique set of barriers.

Conflict of interest statement

Conflict of Interest: No conflicts of interest for PANC, KB, TB, MH. PPL is a consultant for Genentech and Novartis, and has stock in Pfizer, Merck, GSK, Medco Health Solutions,Vital Springs Health Technologies. ALR is a consultant for Merck, Allergan, Cipla Pharma, a medical monitor for Sucampo, on the Scientific Advisory Board for Aerie Pharmaceuticals, and has stock and stock options in Glaukos and Aerie Pharmaceuticals.

Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Prevalence of Important Barriers to Medication Adherence

The items on the survey describing barriers to medication adherence asked subjects to rate the importance of eleven commonly cited reasons that make it “hard for patients to take glaucoma eye drops.” Subjects rated whether each of these eleven barriers was important to them on a visual analogue scale (VAS) anchored between “strongly agree” and “strongly disagree.” Figure 1 shows the percent of adherent and non-adherent subjects who rated a barrier as ≥ midpoint on the VAS.

Figure 2. Frequency of Number of Barriers

Percent of subjects, both adherent and non-adherent, who rated different numbers of barriers as important.