Disclosures: Mansberger reports no relevant financial disclosures.
October 20, 2020
3 min read

Newly developed tool can identify factors that affect glaucoma medication adherence

Disclosures: Mansberger reports no relevant financial disclosures.
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The Glaucoma Treatment Compliance Assessment Tool is an efficient way to determine patient-specific factors that affect glaucoma therapy adherence, according to a study.

The GTCAT is an efficient method for ophthalmologists to predict glaucoma therapy adherence, study co-author Steven L. Mansberger, MD, MPH, told Ocular Surgery News.

“We’ve shown this survey predicts adherence factors, is psychometrically sound in all types of glaucoma patients with all types of adherence, and hopefully in the future we’ll be able to use this survey electronically or in another efficient manner to understand what makes patients have difficulty using their eye drops and address these issues,” he said.

Steven L. Mansberger, MD, MPH
Steven L. Mansberger

Researchers used the GTCAT to identify the health behavior factors related to glaucoma adherence in a population of patients with self-reported poor adherence. The Chang Adherence Measure and the Morisky Medication Adherence Scale were used to identify patients with poor self-reported glaucoma medication adherence to include in the study.

Researchers included 94 patients in the study and administered the 26-question GTCAT to each. The average glaucoma medication adherence for the cohort was 73.8%.

A Rasch analysis showed the survey had no differential bias and was a good overall fit with the patients, according to the study.

“This was the first time we’ve ever used the tool with patients with poor adherence. The tool performed very well. There is a field called psychophysics, which can determine whether or not a survey is measuring what it is purporting to be measuring. The GTCAT performed very well on these psychometric measures,” he said.

The GTCAT identified many factors associated with poor adherence. Mansberger said 50% of patients in the study needed more education on glaucoma, 60% did not use reminders of when to take their glaucoma therapy and at least 40% reported difficulty using the drops.

Improving adherence

The results from the survey can be used to tailor strategies to improve patient adherence. For those who reported difficulty using the drops, Mansberger said a physician could possibly focus efforts on teaching better eye drop delivery techniques or how to use a delivery aid.

Mansberger said he developed the GTCAT about 7 years ago through a researcher grant from the American Glaucoma Society. Originally a 51-item survey, the survey now consists of 26 to 27 questions, and it has started to pay dividends for the researchers.

“The survey makes it very efficient to figure out what factors are related to adherence in a particular patient. My caveat is we haven’t completed a study yet to show that by using this survey, we can improve adherence,” he said.

In the past, clinicians have had to walk through several scenarios with patients to explore why adherence is poor. Now, the survey can be administered at the beginning of every appointment to determine patient-specific factors as to why adherence is poor, he said.

The questionnaire allows the physician to focus on patient-specific issues that are related to poor adherence, including issues that may be sensitive for patients to discuss, he said.

“If they tell you their mom went blind from glaucoma and they don’t think there is anything they can do to prevent blindness, then you can talk to them about the importance of drops and how they’ll decrease their risk of worsening by about 90%. Or if they say they can’t afford drops, you can deal with that and get them on generic or less expensive medications,” he said.

The tool allows physicians to focus education and make care more efficient. The next step, Mansberger said, is to conduct a similar study using the tool to determine adherence barriers and then treat those factors.

That study will determine whether or not focused interventions improve adherence over time, he said.

“It will be an important step in addressing glaucoma therapy adherence,” Mansberger said.