October 23, 2014
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Target IOP a key issue in glaucoma management, reduction of costs

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Establishing, achieving and maintaining target IOP are key points in the management of glaucoma. Target IOP also has a decisive impact on the reduction of direct and indirect glaucoma-related costs, according to one specialist.

Target IOP is the IOP that ensures only minimal progression of glaucoma. In the European Glaucoma Society (EGS) guidelines, it is also defined as “the upper limit of the IOP estimated to be compatible with a rate of progression sufficiently slow to maintain vision-related quality of life.”

Frances Meier-Gibbons, MD

Frances Meier-Gibbons

 

“The aim, in other words, is to reduce the ganglion cell loss to the normal loss related to aging, which is about 0.4% per year. With glaucoma, the decrease is 1.4% per year, and we want to bring it back to the rate of a normal eye,” Frances Meier-Gibbons, MD, said in an interview with Ocular Surgery News.

Target pressure

Target pressure, she said, should be not a number, but a range — for example, between 12 mm Hg and 15 mm Hg. EGS guidelines also state that no single target IOP level is appropriate for every patient and each case needs specific evaluation in relation to a number of variables.

“The stage of the disease, first of all, has to be considered. The more advanced the glaucoma, the lower the target pressure should be. Also, the lower the untreated IOP levels, the lower the target should be. Age plays an important role, and younger patients with a longer life expectancy will require a lower target IOP. On the other hand, glaucoma in older patients, especially pseudoexfoliative glaucoma, can progress rapidly, which requires a lower target. Other factors, such as refraction abnormalities, race, corneal thickness, vascular factors and family history, should be considered,” Meier-Gibbons, an OSN Europe Edition Board Member, said.

No nomogram exists to assist physicians in their choice. The overall situation of the patient is evaluated, a target pressure is established, treatment is administered, and then the patient is monitored. If progression still occurs, the target IOP needs to be set lower.

“Target pressure is a constantly changing variable,” Meier-Gibbons said.

Establishing it in terms of range rather than an absolute value also has important legal implications.

“An absolute value that has not been achieved can make you vulnerable in case of a lawsuit,” Meier-Gibbons said.

Issues of cost, compliance

Achieving and maintaining IOP within a target pressure range allows a considerable reduction of costs, Meier-Gibbons said.

“If glaucoma is stable and does not progress, also the costs are stable because fewer examinations, fewer medications and no change of therapy are needed. Studies demonstrate that best outcomes and cost-effectiveness are obtained when the target IOP is achieved early in the course of treatment,” she said.

There are relatively few health economic studies on glaucoma, and even fewer include indirect costs as part of the burden of the disease, Meier-Gibbons said.

“The issue of glaucoma and cost is poorly addressed in the literature,” she said. “No wonder, since in 2007, a Finnish study showed that 80% of the ophthalmologists did not know the basics of health economics. And yet, cost is a raising issue all over the world, and more studies are needed.”

Moreover, most health economic studies on the cost of glaucoma consider only the direct costs of medical therapy, which are only the tip of the iceberg, she said.

“Very few studies look at the indirect costs related to the loss of vision and consequent loss of independence, need for support and services. Indirect costs amount to at least double the cost of treatment,” Meier-Gibbons said.

Compliance is another key issue to be evaluated in relation to target pressure. Only good compliance allows stable IOP-lowering results as well as cost containment.

As stated in the EGS guidelines, no drug can work unless it is taken, and patients often progress because they do not use their drops regularly.

“Improving compliance is a priority. Patients should be made aware of the major impact of good compliance on the course of the disease, and we should be aware of the major impact of compliance on the social costs of glaucoma,” Meier-Gibbons said. – by Michela Cimberle

Disclosure: Meier-Gibbons is consultant for Alcon and Allergan and receives travel expenses from MSD, Santen and Théa.