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Examining the link between adherence and costs in glaucoma care
Ophthalmologists should continue to work toward improving patients' adherence to prescribed therapies.
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“Maximizing patient adherence to medication has the potential to reduce the number of surgical interventions required to treat glaucoma, prevent unnecessary vision loss and save the overall health care system money in the long run.”
– Alan L. Robin, MD
Due to the growing prevalence of glaucoma, the costs of glaucoma care are rising worldwide. They differ substantially from country to country, depending on many factors. Medications are one of these factors and an important part of the overall cost.
However, many studies indicate that the adherence rate of patients to prescribed glaucoma medication is remarkably low.
Is there a connection between the cost of glaucoma medications and adherence? In reviewing the literature, there are not many studies examining connections between glaucoma medication costs and adherence. Based on European Glaucoma Society guidelines, the definition of adherence (or the synonym, compliance) includes the cooperation of the patient with the recommendations given by the treating doctor; persistence, on the other hand, is defined as the length of time during which the patient takes the medication as prescribed.
Why do glaucoma patients demonstrate reduced adherence (in some studies only 30% to 70%) and persistence (in one study only 25% after 12 months)?
Adherence rate
Several factors influence a patient’s adherence rate. Tsai systematically studied the common obstacles to medication adherence and grouped them into four categories: situational and environmental factors, medication regimen, patient factors and provider factors.
Newman-Casey identified the 11 most common hindrances to optimal glaucoma medication adherence and found that low self-efficacy, forgetfulness, difficulty with drop administration and the medication schedule were factors associated with poor adherence. She noted that these factors must be addressed individually to improve a patient’s medication adherence.
Adherence is evaluated by direct and indirect methods. The direct methods include patients’ observation and measurement of the concentration of a drug metabolite in their urine or blood. Indirect methods are the physician’s estimation of a patient’s adherence, the patient’s self- reporting, the evaluation of pharmacy refill rates and the utilization of electronic medication monitors.
Friedman published the GAPS study in 2007, which used health insurance claims as the key source of information about the adherence of patients. He found that only 10% of the patients had refilled their index medication at 1 year.
Muir noted that adherence to medications consists of four steps:
1. Obtain the medication.
2. Instill the drop successfully in the eye.
3. Use the medication at the appropriate time.
4. Repeat all of this, every day.
In a study, Robin showed that patients who were prescribed a drop twice daily often had more problems with time-appropriate dosing than patients with a once-daily regimen.
It is not only the regularity of administration that is a problem for some patients, but the actual application of an eye drop can also be more complicated than swallowing an oral drug. Stone showed in a study that only 31% of patients were able to administer an eye drop correctly, although 93% of those questioned claimed they had no problems in doing so. This is a typical example of the often seen fact that self-reported adherence is mainly overstated by patients, as found by Okeke.
We should not underestimate the fact that patients may be unwilling to admit nonadherence because they want to make a good impression on their treating doctor.
What type of patient is more adherent? Djafari, in a descriptive study of 181 patients, said that patients who lived alone, were widowed and used fewer medication were more adherent. The authors stated, as others have, that treating physicians were often unable to predict which patients were adherent.
Many studies show adherence is improved with a simpler regimen.
Improving adherence
Why is it important to improve the adherence of patients? Robin gave an example: A patient who misses one dose of a once-daily glaucoma medication once a week misses more than 6 weeks of therapy per year.
In internal medicine, poor adherence can lead to more emergency hospital admissions and, therefore, to a tremendous increase in health care costs, according to Osterberg.
Many studies have dealt with the question of how to improve adherence. Rodrigues noted that adherence could be improved with better education concerning the disease, an improved doctor-patient relationship and an increased therapy supply.
Friedman noted how important doctor-patient communication is: He showed in a retrospective study that communication and health-related beliefs of patients were important parts of adherence.
Are there practical tips on improving adherence? The American Glaucoma Society carried out a Patient Care Improvement Project and defined three categories of advice:
1. Practical tips and tools (eg, appointment reminders).
2. Ideas for drug companies (eg, modification of bottle design for easier handling).
3. Triggering and supporting self-care impulses by explaining the nature of the disease.
A study by Lim showed, however, that the often used “this drop helps you” did not improve adherence.
The Norwich Adherence Glaucoma Study divided patients into two groups: One group received standard clinical care, and the interventional group received more glaucoma education and a motivational support package. Adherence was measured electronically. Interestingly, there was no difference in the adherence patterns of either group, but the patients in the interventional group were more satisfied.
A balanced approach
One might assume that with increased patient education and simplified glaucoma therapies, especially since the introduction of once-daily prostaglandin therapies, patient adherence would improve altogether. Studies have shown, however, that adherence rates have not improved in recent years. It is critical to find a balance between patients not taking their disease seriously and intimidation of the patient.
One study by Nelson showed that the knowledge of having a potentially blinding disease alone leads to a reduction in quality of life. Even so, it is mandatory to inform patients that in 16% of cases, untreated glaucoma can lead to unilateral blindness after 10 years, Wilson said.
The choice of which glaucoma therapy itself is an important factor for a patient’s potential nonadherence. We know that two-thirds of all glaucoma patients have significant side effects from their therapy, which may reduce adherence, according to separate studies from Patel and Zimmermann. It is important to discuss this issue with patients and learn whether or not they are comfortable with their prescribed therapy.
Cost issues
The issue of cost has also led to major discussions concerning glaucoma therapy. In recent years, branded products have been increasingly replaced by generics. The cost of generic medication is often lower than branded products, but there are studies demonstrating that generic medication can differ quite substantially from their branded counterparts. Concerning prescription habits, it is interesting to see that there is a large difference among various countries in Europe, with a descending gradient from north to south.
Because costs of glaucoma medications influence the adherence of patients, it is the duty of each ophthalmologist to find an appropriate therapy for each patient.
To return to the question asked initially: Does a connection between adherence and costs in glaucoma treatment exist? The link factors are likely to be the progression and the severity of the disease.
Studies have demonstrated that there is a connection between the severity of the disease and treatment costs.
However, few studies exist examining adherence and the progression of glaucoma. Tsai found, in an interesting study, that greater daily IOP fluctuations, which may be influenced by nonadherence, could lead to greater progression of the disease.
The influence of these IOP fluctuations on glaucoma progression is still controversial, and perhaps more studies are needed to get a clear answer.
But one fact is certain: If IOP is not well controlled (for example, because of suboptimal treatment), disease progression is more likely. Large studies, such as the Collaborative Normal Tension Glaucoma Study and the Early Manifest Glaucoma Trial, have shown that treatment of elevated IOP delays the progression of visual field loss.
SIGMA is an ongoing study on incentives for glaucoma medication adherence, and it will evaluate the extent to which value pricing can improve medication adherence. The estimated study completion date is January 2017, and the initial results will prove informative.
Perspectives
In summary: The role of adherence in the costs of glaucoma care still requires more intensive studies. In my opinion, there is a clear link among nonadherence, progression and costs in glaucoma care, and it is our duty as ophthalmologists to work toward improving patients’ adherence to their prescribed therapies.
Questioning various glaucoma specialists in the U.S. and Europe about costs and adherence in glaucoma management has revealed interesting comments:
1. There is a clear agreement that adherence influences costs.
2. Many colleagues use electronic devices to attempt to improve adherence (for example, smartphones).
3. Many say that the most important tool is talking with patients about their disease and therapeutic needs.
Donald L. Budenz, MD, MPh, (U.S.) mentioned the importance of educating patients about the potentially blinding nature of the disease. Anton Hommer, MD, (Austria) added that it is important to detail to the patient the problems (for example, losing their driver’s license). Steven J. Gedde, MD, (U.S.) mentioned the fact that therapies must be simplified and treatments adjusted to the patient’s lifestyle.
George L. Spaeth, MD, (U.S.) emphasized the key role of personalized care, which in his opinion is mandatory for each patient.
Ingeborg Stalmans, MD, PhD, (Belgium) and Alain Bron, MD, (France) both added that physicians should promote effective therapies that are patient, and therefore also adherence, independent.
Generic medications are often used, but there is a wide range from “no generics” to “widespread use of generics.” The use of generics depends on the country of practice. However, it is universally agreed that it is important to determine the therapy that best suits each patient and best fits into that patient’s life.
Leopold Schmetterer, PhD, (Austria) noted that we could reduce costs by stopping treatments in patients who do not need them. The same comment was made by Spaeth, who added that in caring for glaucoma patients, testing must also be individualized as needed to best benefit each patient’s ultimate outcome.
The author would like to thank Michael S. Berlin, MD, USA, for the critical review of the manuscript.
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- For more information:
- Frances Meier-Gibbons, MD, is an OSN Europe Edition Board Member. She can be reached at Eye Center Rapperswil, Merkurstrasse 50, CH-8640, Rapperswil, Switzerland; email: frances.meier@bluewin.ch.
Disclosure: Meier-Gibbons reports she is a consultant to Alcon, Allergan and Théa.