Study targets topical medication adherence, visual field progression

This article was reviewed by Donald S. Fong, MD, MPH

Research is focusing on topical medication adherence and visual field progression in open-angle glaucoma (OAG).

At the 2020 meeting of the American Glaucoma Society (AGS), Donald S. Fong, MD, MPH, of Kaiser Permanente Southern California (KPSC), presented a study designed to assess the effect of treatment adherence to topical glaucoma medications on visual field progression, using data from clinical practice.

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Not surprisingly, the study found that poorer medication adherence was significantly associated with a faster rate of visual field decline.

Elevated IOP is the only modifiable risk factor to reduce the risk of progression in OAG, and first-line treatment is typically topical ocular drops to lower IOP.

“Low medication adherence may increase the risk of damage from glaucoma, but there is a lack of quantitative data on the relationship between treatment adherence and glaucomatous visual field progression,” Fong said.

Related: Emerging therapy for open-angle glaucoma

Real-world study
To address the lack of data, Fong and colleagues examined records from KPSC, an integrated health system that provides comprehensive care to over 4.6 million members.

Fong noted several benefits of utilizing this population.

“In our integrated health system,” he said, “KPSC members receive their prescriptions from a single source, and patients tend to be long-term members of the health plan.”

He explained that this allows for tracking patient refills, and makes long-term followup possible. The population is also representative of the state of California for racial diversity.

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Study details
For the study, patients meeting inclusion criteria were stratified by severity of baseline visual field measurements, using readings from 6 months before and after the index date.

For patients that had no visual field measurements in the time frame, their baseline disease severity was designated as “missing.”

Adherence was measured by proportion of days covered, which was determined as the number of days that the patient was supplied with medication, divided by the number of days in the period of interest.

Patients who received multiple medications were considered adherent if 1 or more of their medications was filled, and adherence was reported in categories of low, moderate, and high.

Related: Pharmacologic treatment an option for open-angle glaucoma

The investigators hypothesized that the interaction between adherence and time would be positive. In other words, for a given follow-up time, patients with better adherence would have better mean deviation (i.e., less severe disease).

“Our study is the first to use real-world data to quantify the impact of non-adherence on glaucoma progression,” Fong said. “We demonstrated that treated glaucoma patients who were more adherent showed less loss of visual function. We need to improve patient adherence to medications because higher adherence will delay glaucoma progression and loss to a patient’s quality of life.”

Read more by Steve Lenier

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Donald S. Fong, MD, MPH
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Dr. Fong has no financial disclosures related to this subject.