Increased first-year contact may improve long-term glaucoma medication adherence

A study used group-based trajectory modeling to determine patterns of adherence.

Issue: December 25, 2015

Educational interventions, disease-management strategies and monitoring of glaucoma patients during the first year they take newly prescribed medications may improve adherence in the long term, according to a study.

Systematic reviews estimate that nonadherence rates for glaucoma medication can be up to 80%, and poor adherence can lead to risk periods of uncontrolled IOP, more severe eye damage or blindness from glaucoma progression, the study said.

“Glaucoma is a disease where you get no symptoms until very late in the disease process,” first author Paula Anne Newman-Casey, MD, MS, told Ocular Surgery News. “So that’s one of the reasons that I think people have such a hard time continuing with their glaucoma medications. They have no symptoms, and they are still going to need to take that medication for the rest of their life.”

An established approach to quantifying adherence is to use the medication possession ratio (MPR) from pharmacy refill data, but it does not determine the varying patterns of patients within the same adherence group.

“When we were thinking about looking at people over 4 years, we were thinking to ourselves, ‘Does an 80% MPR really capture the complexity of the behavior that goes into refilling a prescription?’” Newman-Casey said. “And then we thought, if we could look more at patterns of filling behavior, that may give a more nuanced view into how patients may deal differently with adherence.”

Group-based trajectory modeling

Using group-based trajectory modeling, the retrospective, longitudinal cohort study analyzed 1,234 nationwide managed care network beneficiaries who were newly diagnosed and treated for open-angle glaucoma with more than 4 years of follow-up.

At 1 year, 7.5% of enrollees were never adherent (group 1), 14.9% had persistently very poor adherence (group 2), 9.5% had declining adherence (group 3), 48.1% had persistently moderate adherence (group 4), and 20% had persistently good adherence (group 5). At 4 years, 15.6% of enrollees were in group 1, 23.4% were in group 2, 9.1% were in group 3, 37% were in group 4, and 15% were in group 5.

Nearly all of those with the worst and best adherence patterns in the first year maintained their adherence patterns throughout the 4-year follow-up. With almost half of beneficiaries having persistently moderate adherence in the first year, approximately one-third of those patients had worsened adherence over the 4-year follow-up.

Increased physician contact

Patients who exhibited the best adherence over 4 years were more likely to be older, to be white, to earn more than $60,000 per year, and to have an increased number of visits with eye care providers, a decreased medication copayment cost and no reliance exclusively on store pharmacy pick-up for prescription refills.

“While we had a few other factors that seemed to predict better adherence, like being older or earning more money, those are not things that we can intervene on, but having increased contact with the health care system is definitely something that we can work on to improve patient self-management,” Newman-Casey said.

Newman-Casey hopes to improve health education by extending the reach of physicians using health educators to help better counsel patients and help them manage and take control of their glaucoma.

“I think one of the most important things is just to ask patients how they’re doing with their medications, and if they are having any trouble forgetting to take them or having any side effects or any problems with cost, and probe a little to see if they’re really taking the medication,” she said. – by Kristie L. Kahl

Reference:
Newman-Casey PA, et al. Ophthalmology. 2015;doi:10.1016/j.ophtha.2015.06.039.

For more information:
Paula Anne Newman-Casey, MD, MS, can be reached at University of Michigan, Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, 1000 Wall St., Ann Arbor, MI 48105; email: panewman@med.umich.edu.

Disclosure: Newman-Casey reports no relevant financial disclosures.