Lower cost could be a factor, researchers say
A new study shows that high drug cost could be keeping glaucoma patients from taking their medication as prescribed, putting them at risk for irreversible blindness. Researchers believe that one way to solve this problem may be switching to more affordable, generic drug options.
Nearly 3 million Americans over the age of 40 have glaucoma, which increases pressure inside the eye and can cause blindness. Despite the availability of effective glaucoma treatments that can prevent vision loss, more than half of glaucoma patients do not take their medication as prescribed. Researchers have been trying to find what factors impact whether or not patients stick to their medication regimen (known as adherence).
"Some of my patients require three or four different classes of medications, sometimes paying more than $100 per month in out-of-pocket costs," said Joshua D. Stein, M.D., the lead researcher. "If we can find ways to reduce the cost of medications, we would have one less barrier that can impact adherence."
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Typical treatment for the most common form of glaucoma, open-angle glaucoma, includes prostaglandin analogues (PGAs). These medicated eye drops lower pressure inside the eye and can help preserve vision. While these prescription drugs are highly effective, the brand name versions can be costly.
The first and only generic PGA, latanoprost, was introduced in the United States in 2011. A typical patient could expect to save approximately $1,300 a year by switching to it from a brand name. To determine how the generic drug’s availability may have impacted adherence, researchers from the University of Michigan examined data from nearly 8,500 glaucoma patients for the 18 months before and after generic latanoprost became available.
Results showed that medication adherence improved on average among all patients who switched to generic latanoprost. Improvement was greater among those who had been on name brand PGAs other than branded latanoprost.
In addition, among patients who had poor adherence when only brand name versions were available, researchers found a distinct connection between cost and improved medication adherence. The greater the difference in copay between a brand name and generic drug, the better patients became at taking their medication as prescribed. The researchers speculate that the lower cost of generic latanoprost may be the primary reason.
They also found that improvement in medication adherence was notable among African-American patients who switched to the generic drug once it became available after having had poor adherence. African-Americans tend to have more severe glaucoma compared to other ethnicities and therefore often have a more complex medication regimen, which affects both cost and adherence, according to the study.
The researchers advise people with glaucoma to speak with their ophthalmologist about whether any of their prescribed medications are available as generic products and if they could be switched to such products if appropriate.
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