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Treatment of ocular hypertension cost-effective for certain patients
Economic model was designed to build upon an earlier study that showed therapy is worthwhile in those with specific risk factors.
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Treating all patients with ocular hypertension was less cost-effective than treating selected patients with specific risk factors, a recent study showed.
The study authors identified economic and clinical thresholds in which treating ocular hypertension was cost-effective and clinically useful in preventing the condition from progressing to glaucoma.
William C. Stewart, MD, and colleagues assessed the cost- effectiveness of treating ocular hypertension in the United States. The primary outcome measure was the long-term cost-effectiveness of treating ocular hypertension to prevent the onset of glaucoma. They reported their findings in Ophthalmology.
“We wanted to determine a way to help clinicians know if their patients should be treated for ocular hypertension or not,” Dr. Stewart told Ocular Surgery News in a telephone interview. “There are several approaches to this. One, of course, is to look at long-term outcome studies to show incidence of progression over time. The second method is an economic method.”
Clinical and economic studies to date have not adequately addressed guidelines for proper treatment of ocular hypertension, Dr. Stewart said.
Determining who should be treated
In performing a cost-effectiveness analysis, the authors adapted risk factors and practice patterns from the Ocular Hypertension Treatment Study (OHTS). They also collected unit costs for medications from geographically diverse pharmacies, patient visits, diagnostic procedures and treatment regimens from Blue Cross/Blue Shield data for a 5-year period.
“The OHTS trial was such a great study because it answered the question: Is it worthwhile to treat? Yes.” Dr. Stewart said. “Now, the question still is: Who?”
The OHTS trial showed that it was valuable to treat patients with ocular hypertension because those patients who were treated progressed to glaucoma less often than those who were not treated, he said.
However, the OHTS study was not designed to completely determine the level of ocular hypertension that should be treated or which patients should be treated, Dr. Stewart said.
He and colleagues focused on four primary risk factors identified in OHTS: age, IOP, corneal thickness and cup-to-disc ratio. Treating patients with a certain level of those risk factors was deemed more cost- effective and clinically useful because the risk factors were considered most likely to lead to glaucoma, he said.
“We used these same four risk factors out of OHTS, and we then used a Markov model to determine who should be treated on an economic basis vs. a clinical basis,” he said. “Of course, this is important for payers to determine if it’s a condition that’s worthwhile to treat and, if so, which specific patients and at what level of severity.”
The study authors used one cost-effectiveness benchmark, the NICE Classification, which determined that $50,000 to improve one patient’s quality of life through treatment for ocular hypertension was cost-effective, Dr. Stewart said.
Incremental cost-effectiveness
Dr. Stewart and colleagues used OHTS data to calculate an “incremental cost-effectiveness ratio” (ICER) for preventing one ocular hypertension patient from developing open-angle glaucoma. The ICER for preventing one patient from developing open-angle glaucoma was $89,072, not adjusted for risk factors, according to the study abstract.
However, minimally cost-effective ICERs, according to risk factors, were: age of 76 years ($45,155); IOP of 4 mm Hg more than the average pressure of 25 mm Hg ($46,748); central corneal thickness 40 µm less than the average thickness of 573 µm ($36,683); and vertical cup-to-disc ratio 0.2 wider than the average ratio of 0.4 ($35,633), the abstract said.
Treating all ocular hypertension patients would cost almost $80,000 per patient, which is “not worthwhile” according to the NICE Classification, Dr. Stewart said.
“There are really few guidelines on how to treat ocular hypertension. Therefore, some doctors don’t treat any of these ocular hypertension patients.
“In addition, other doctors I know, and even some specialists, will call all or some of their OHT patients ‘glaucoma,’ just so they feel good about treating them, strange as it may seem,” he said. “So there’s little consensus still about how to treat OHT patients.”
Dr. Stewart noted that many other studies have pointed to other potential risk factors, such as race, cardiovascular disease and diabetes.
“Are these really not risk factors and not playing any role in these ocular hypertension patients?” he said. “I think they probably are. They just didn’t show up in OHTS.”
Also, the OHTS study was relatively small, comprising only 1,600 patients. Dr. Stewart called for larger studies and more extensive data to shed light on clinical and economic factors related to treatment of ocular hypertension.
“You look at what is done in systemic literature, in terms of determining treatment guidelines. These are done with thousands of patients,” he said. “My hope would be that it would push us all to study the problem more fully and come up with more definitive clinical and economic guidelines.”
For more information:
- William C. Stewart, MD, can be reached at 7001 LBJ Freeway, Suite 700, Dallas, TX 75244; 843-762-6500; fax: 800-980-0718; e-mail: info@prnorb.com.
Reference:
- Stewart WC, Stewart J, et al. Cost-effectiveness of treating ocular hypertension. Ophthalmology. 2008;115:94-98.
- Matt Hasson is an OSN Staff Writer who covers all aspects of ophthalmology. He focuses on regulatory, legislative and practice management topics.