The Case for Glaucoma Screening

A look at the effect of early detection on healthcare costs.

BY LAWRENCE D. GOLDBERG, M.D., M.B.A.

In the United States, glaucoma is a significant cause of blindness (an estimated 130,000 such cases exist) and is the leading cause of blindness among African Americans.^1,2 Over a period of 20 years, the risk of legal blindness (20/200 or worse) from newly diagnosed and treated ocular hypertension or primary open-angle glaucoma (POAG) in a Caucasian population is estimated to be 27% in at least one eye, and 9% in both.³

Early identification and treatment are critical in preserving patients' vision. Further, the literature suggests that these strategies may result in significant cost savings⁴ because the cost of treatment increases with the progression of the disease.⁵ Indeed, the importance of early screening and treatment has been reinforced recently with the addition of the Health Plan Employer Data and Information Set (HEDIS) measure for glaucoma screening to the required set of measures for National Committee for Quality Assurance (NCQA) Managed Care Organization (MCO) Accreditation.⁶ Moreover, several other health policy and quality-of-care initiatives have been adopted, including expanded glaucoma-specific preventive benefits for Medicare beneficiaries⁷ and specific glaucoma prevention, detection and management objectives in the U.S. Department of Health and Human Services' "Healthy People 2010."⁸

Nonetheless, many ophthalmologists and managed care organizations ask if glaucoma screening is actually cost effective. In this article, I make the case for the answer of "yes, if directed to at-risk populations."

Glaucoma Prevalence and Impact

At least 2.2 million people in the United States have glaucoma, although nearly half are probably not aware of it,⁹ and another 5 to 10 million have elevated IOP, which when treated in higher-risk individuals, can effectively delay or prevent glaucomatous eye damage. An estimated 2% to 3% of elderly individuals have glaucoma, and another 4% to 7% of people more than 40 years old have elevated IOP without detectable glaucomatous damage on standard tests.¹⁰

The prevalence of glaucoma will rise as the population ages, because older age is a risk factor. In the large, population-based Baltimore Eye Survey, the prevalence of definite or probable POAG nearly doubled from age 40 to 49 years to age 60 to 69 years, and more than tripled for those aged 70 to 79 years.¹¹ Thus, it has been estimated that by 2020, glaucoma is expected to affect an estimated 3.36 million people in the United States, more than a 60% increase from today.¹²

Glaucoma represents a major part of many ophthalmologists' practices, accounting for more than 7 million office visits each year¹³ and the fifth most frequent reason patients returned to their physicians' office. It has the highest return-visit ratio, 4.1:1, ahead of even hypertension (ranked second, 4.0:1).¹⁴

Few in-depth analyses of direct and indirect costs related to glaucoma have been reported to date. The disease has been estimated to cost managed-care organizations $1 billion each year for treatment, and the U.S. government about $1.5 billion each year in Social Security benefits, lost income tax revenues and health care expenditures.¹⁵ The cost in the United States of treating a patient with POAG, beginning with initial diagnosis through 2 years, was estimated in 1998 to be $2,109.¹⁶

An analysis of Medicare beneficiaries with glaucoma showed that, compared with patients with normal vision, excess adjusted mean eye-related costs were $318, $355, and $192 annually for those with moderate loss, severe loss and blindness due to glaucoma, respectively. Further, annual excess non-eye related costs were $2,338, $3,719 and $3,458, respectively. Thus, Medicare beneficiaries with coded diagnoses of glaucoma and vision loss incur significantly higher costs than those with normal vision, and approximately 90% of these costs are non-eye related medical costs.¹⁷ These findings were similar to those of another analysis of Medicare beneficiaries with blindness due to a variety of causes (e.g., glaucoma, macular degeneration and diabetic retinopathy). When the findings were extrapolated to the entire Medicare population, the analysis showed blindness and vision loss were associated with $2.14 billion in 2003 non-eye related medical costs.¹⁸

Less quantifiable but no less real is the enormous personal impact glaucoma has after it progresses to significantly impair vision, diminishing general¹⁹ and vision-related²⁰ quality of life.

Support for Glaucoma Screening

A number of medical organizations and government agencies — including the American Academy of Ophthalmology (AAO),²¹ the Veterans Administration (VA)²² and the National Institutes of Health (NIH)²³ — have developed consensus statements or guidelines supporting early glaucoma detection and treatment. Also, as previously mentioned, the U.S. Centers for Medicare and Medicaid Services (CMS, formerly the Health Care Financing Administration) grants Medicare coverage of regular glaucoma screenings for high-risk individuals, which includes those with diabetes, those with a family history of glaucoma, African Americans over the age of 50 and hispanics 65 and older (new addition to the benefit in 2006).²⁴ Other general support for glaucoma screening and treatment include the National Eye Institute (NEI)-sponsored National Eye Health Education Program with the objective of educating the public about the importance of early detection and treatment of glaucoma and diabetic eye disease.

The most widely accepted guidelines in the United States for screening and management of glaucoma come from the AAO.²¹ They serve as a guide to providing quality eye care while considering the current environment of managed care and changing healthcare delivery standards. The recommendations for glaucoma detection and management are based on a rational, evidence-based, cost-efficient three-tier approach:²⁵

1) All individuals, especially the elderly and African-Americans, should undergo periodic screenings with a dilated-eye examination and a measure of IOP to identify individuals with ocular hypertension who are at risk for glaucomatous eye damage

2) Individuals with elevated IOP should then undergo further testing to determine baseline optic-nerve damage, and receive medication to reduce IOP

3) Patients with baseline optic-nerve damage should be followed more aggressively using available diagnostic technology to assess success of treatment and control of glaucoma progression.

Early detection is critical to prevent or minimize glaucomatous eye damage and disease progression.²⁶ However, studies have shown that optic-nerve damage may be associated with IOP levels below the usual screening cutoff,^27,28 and that some individuals with elevated IOP may never develop glaucomatous damage.^28,29 Therefore, the POAG Preferred Practice Pattern recommends also assessing optic nerve status as part of screening examinations, though it recognizes that these assessments are cumbersome and not well suited for broad screening. The most practical method for widespread screening of targeted populations — before glaucoma suspects are subjected to these additional evaluative techniques — is to identify risk factors (Table 1), assess IOP and perform a dilated-eye examination with attention to the optic disc.²⁵

Guidelines for Screening

Although there is no perfect, single screening protocol for glaucoma, it is generally agreed that a comprehensive ophthalmic examination for adults with vision problems should routinely include screening for glaucoma. Indeed, most glaucoma patients in the United States are detected through routine eye exams.³¹ However, the 2005 results of the HEDIS measure among Medicare plans shows that the rate of glaucoma screening was 62.4%,³² suggesting there is much room for improvement.

It is worth noting that because even some patients with IOP in the normal range develop glaucomatous damage, glaucoma experts increasingly recognize that detection and management of this disease requires approaches beyond targeting IOP alone. Research suggests that neurodegenerative processes are a central mechanism underlying the development and progression of glaucoma.³³ AAO's POAG clinical practice guidelines have modified treatment goals that include neuroprotection as well as IOP reduction.

While none of the current ophthalmic or oral agents used to manage glaucoma have been approved for neuroprotection, research is underway on potential agents, including: memantine, an NMDA receptor blocker, currently approved for the treatment of dementia; riluzole, a glutamate regulator approved for amyotrophic lateral sclerosis; dextromethorphan, a weakened form of a main narcotic ingredient used in cough syrups; brimonidine, a selective alpha-adrenergic agonist currently used topically to decrease IOP; glatimir, an injectable agent administered subcutaneously and approved for multiple sclerosis; and others.³⁴ Currently in Phase 3 trials, memantine has the most advanced clinical data in humans.

Screening Cost Effectiveness

The expense of screening individuals and treating newly identified patients raises the question of who should undergo screening. It is generally held that the most cost-effective screening programs are those that target high-risk patients for early detection. However, the Ocular Hypertension Treatment Study³⁵ showed that controlling IOP in patients who have elevated IOP but not a diagnosis of glaucoma can prevent or delay the onset of POAG, suggesting that a well-designed screening strategy may prove more cost-effective than previously appreciated.

British researchers estimated the cost of glaucoma screening to be approximately $850 per patient³⁶ and concluded this cost could be justified if, over a lifetime, an equal or greater healthcare expenditure can be saved or if the economic impact on a patient exceeds it. They also determined that, based on the life expectancy of people age 40 to 59, screening them — despite their lower prevalence of glaucoma — would result in approximately the same economic benefit as would screening older patients (60+).

Data that treatment becomes much more expensive as glaucoma progresses¹⁷ further suggest that earlier screening and treatment saves costs despite a longer timeframe of treatment. For example, using cost data from a U.S. multicenter retrospective study⁴ and clinical outcome data from the Advanced Glaucoma Intervention Study,³⁷ we showed that, over a 14-year period, if screening was performed and treatment began in year 1, little progression occurred, and the total treatment cost for 14 years was approximately $8,900. However, if screening was performed and treatment began in year 8, significant progression had occurred, and the total treatment cost for just 7 years was approximately $10,500.³⁸

From a payer perspective, positive return on investment (ROI) for screening and care management programs has generally been limited to those directed at congestive heart failure or multiple disease conditions.³⁹ However, in a model to evaluate the potential ROI of a glaucoma-screening program in commercial vs. senior member populations, we demonstrated a potential positive ROI in both managed-care populations.⁴⁰ In a commercial population, total annual costs to "screen and treat" vs. a strategy of not screening were $0.62 per member per month (PMPM) vs. $0.80 PMPM respectively (a net savings of $0.18 PMPM in favor of screening). In a senior population, these costs were $6.66 PMPM vs. $7.94 PMPM, respectively (net savings of $1.28 PMPM in favor of screening). With estimated program costs of $0.009 PMPM and $0.167 PMPM in the commercial and senior populations, respectively, the estimated ROI was $2.57 and $1.75 for these programs (see Table 2). The positive ROI values can be explained by the significant differences in annual costs by stage of disease and the relatively modest costs associated with a glaucoma screening program.

The Evidence Is In

Numerous medical organizations and government agencies have supported early diagnosis and treatment for glaucoma. Screening in older adults is now part of NCQA MCO Accreditation. Recent studies suggest that broad-based screening in adults, even as early as age 40, is cost effective. While there is no perfect glaucoma screening test, routine eye exams, with additional confirmatory tests in glaucoma suspects and those at high risk, appear to represent a cost-effective approach. In sum, the evidence for early screening and treatment is in; what remains is to act upon it. OM

References

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Lawrence D. Goldberg, M.D., M.B.A. is the founder of Goldberg, MD & Associates, in Battle Ground, Wash., a healthcare consulting practice focused on medical management and marketing strategy. He has been a consultant to several healthcare companies including Allergan, Pfizer and Serono. He reports no financial interest related to this article. You can contact him via e-mail at doctorg9@ix.netcom.com.