Predicting Adherence With the Glaucoma Treatment Compliance Assessment Tool

Abstract

PRéCIS:: Univariate and multivariable models using the Glaucoma Treatment Compliance Assessment Tool (GTCAT) statements identified multiple, patient-specific factors associated with adherence that could be used to inform personalized interventions to optimize glaucoma adherence.

Purpose: The purpose of this study was to determine the health behavior factors related to glaucoma adherence in patients with self-reported poor adherence.

Methods: A research coordinator used the Chang Adherence Measure and the Morisky Medication Adherence Scale to identify subjects with poor self-reported glaucoma medication adherence and enrolled them in a 3-month study to electronically monitor medication adherence. At enrollment, the coordinator administered the GTCAT. We calculated the percentage of prescribed doses taken over a 3-month period using an electronic dose monitor (AdhereTech). We used Rasch analysis, and univariate and multivariable regression to determine the GTCAT statements that predicted electronically monitored adherence.

Results: The mean adherence was 73.8% (SD=21.04%, range: 13% to 100%). Rasch analysis showed that the GTCAT had a good overall fit and no differential bias (Anderson likelihood ratio test >0.05). Multiple GTCAT statements were associated with adherence, which represented increased knowledge, increased cues-to-action, decreased barriers, less depression, and increased self-efficacy (P<0.09 for each). The full GTCAT or a subset of statements had a high association with adherence (R range: 0.44 to 0.51, P<0.005 for all). The GTCAT identified >50% of patients who wanted more education about glaucoma; >68% who did not use reminders; and >40% who reported having difficulty using the eye drops.

Conclusions: The GTCAT identified multiple factors associated with adherence. Clinicians and researchers could use this tool to identify specific barriers to adherence and develop potential interventions to improve adherence.

Trial registration: ClinicalTrials.gov NCT03159247.

Conflict of interest statement

Conflict of Interest: the authors have no conflicts of interest to disclose.

Figures

Figure 1.

Distribution of answers with the corresponding percentage for the 25 statements of the Glaucoma Treatment Compliance Assessment Tool. Support, Educate, Empower (SEE) study 2020.

Figure 2.

Person-item map from the Rasch Partial Credit Model demonstrating easier items (rescale 5) to more difficult items (rescale 10). The figure shows a parametric curve without left or right skew distribution suggesting a good distribution of the person parameters with item difficulty. Support, Educate, Empower (SEE) study 2020.