The Cost of Detected and Undetected Glaucoma to Society

“According to a US study, there is a fourfold increase in direct ophthalmology-related costs as glaucoma severity increases” 

Glaucoma is the leading cause of irreversible blindness in Australia and is rapidly increasing in prevalence due to an aging population.^1,2 Other risk factors associated with glaucoma, such as high myopia, are also projected to increase exponentially in the coming decades, creating a potential public health dilemma.^3,4

The global prevalence of glaucoma reached 80 million in 2020 with six million of these patients bilaterally blind as a result of end-stage disease.⁵ The prevalence of glaucoma in Australia is estimated to be 3.7%, which increases to 10% in patients over the age of 80.^6,7 This prevalence is projected to increase by 80% in 2025.⁸

Being a relatively asymptomatic disease, especially in the early stages, a significant proportion of individuals with glaucoma remain undiagnosed. It is estimated that approximately 50% of Australians with glaucoma do not know they have the disease.⁹ This is even greater in minority and/or socioeconomically disadvantaged groups, which have up to 4.4 times greater odds of undiagnosed and/or untreated glaucoma.¹⁰ Even among those diagnosed with glaucoma, many do not receive treatment. An analysis of US Medicare claims data from 1992 to 2002 found that an average of 27.4% of patients with primary open angle glaucoma (POAG) did not receive medical or surgical therapy in a given year.¹¹

In addition to association with worse patient outcomes and increased burden on the health system, delayed diagnosis and treatment also has significant economic implications as the cost of glaucoma increases exponentially with progressive disease.^12,13

ECONOMIC BURDEN OF GLAUCOMA

Glaucoma is associated with significant direct and indirect health costs to the Australian economy. The total cost of POAG to Australia in 2005 was AU$1.9 billion and is estimated to rise to AU$4.3 billion in 2025.⁸ Annual direct health care costs of glaucoma in Australia are expected to increase from AU$355 million in 2005 to AU$784 million by 2025.⁸ This would be considerably higher if all patients were appropriately diagnosed and treated.

Health economic modelling for a patient with newly-diagnosed glaucoma estimates that the average lifetime direct cost of care for people with POAG is about US$137 per patient per year, which is US$1,688 more than for those without glaucoma.¹⁴ This increases to an additional US$2,903 in annual total health care costs for glaucoma patients compared to those without.¹⁵

ECONOMIC IMPACT OF EARLY DETECTION AND TREATMENT

According to a US study, there is a four-fold increase in direct ophthalmology-related costs as glaucoma severity increases from asymptomatic ocular hypertension/earliest glaucoma through advanced glaucoma to end-stage glaucoma/blindness, with mean annual direct medical costs of US$623, $1,915, and $2,511, respectively.¹²

Prescription medications comprise the majority of costs at all severity stages. A similar trend is also seen in Europe, where direct costs of treatment increase by approximately €86 for each incremental increase in glaucoma stage, ranging from €455 per person per year to €969 per person per year in advanced glaucoma.¹⁶

In addition to direct costs, patients with advanced disease incur significant additional indirect costs (e.g. family/home help and rehabilitation costs) that constitute a substantial burden on health care resources and become the predominant driver of overall costs.^17,18 For example, a European study found that the average annual direct health care cost of glaucoma-related blindness was between €429 and €523 per patient.¹⁷ This translated into an annual total cost (including rehabilitation costs and costs to families) of between €11,758 and €19,111.

IMPACT ON OVERALL HEALTH SPENDING

In addition to direct and indirect costs, vision loss from advanced glaucoma can also lead to increased spending on other health care services. It is estimated that approximately 90% of the total costs of glaucoma blindness are non-eye related medical costs.¹⁹ Visual impairment increases risks of falls and accidents,^19,20 hip fractures,^21,22 injury,²⁰ motor vehicle crashes,²³ nursing home placement,²⁴ and mortality.²⁵ Moreover, inadequate vision is related to functional status decline²⁶ and depression.²⁷

A retrospective cohort analysis on a random 5% Medicare sample in the United States quantified some of the above risks among patients diagnosed with glaucoma.²⁷ Patients were stratified into four mutually exclusive categories based on their worst degree of vision loss – no vision loss, moderate vision loss, severe vision loss, and blindness. These categories were derived from the 57 qualitative International Classification of Diseases, Clinical Modification (ICD9-CM) codes for vision loss.

“In addition to association with worse patient outcomes and increased burden on the health system, delayed diagnosis and treatment also has significant economic implications” 

The study demonstrated that glaucoma patients with any degree of vision loss had 46.7% higher total costs compared with those without vision loss, with mean total annual medical costs increasing from US$8,157 for no vision loss to US$18,670 for blindness.²⁷ Frequency of events invariably increased with greater glaucomatous vision loss for all investigated events. In patients who had become blind from glaucoma, 25.3% were placed in nursing homes, 17% had incident depression, 15.5% experienced a fall and/ or accident, 16.9% sustained injury, and 7% fractured a femur. In contrast, no single event exceeded 7.8% in the population without vision loss.²⁷ Patients with vision loss were 2.18 times more likely to be placed in a nursing home and 1.63 times more likely to develop depression compared to patients with no vision loss. Additionally, they were 67.4% more likely to fracture a femur and 58.6% more likely to experience a fall or accident.

COST-EFFECTIVENESS IN GLAUCOMA

To lower the costs associated with glaucoma, we must ensure that patients are detected and treated earlier with safe, effective, and cost-effective options. Cost-effectiveness data provides information about the costs of interventions relative to their performance, which can be helpful in identifying optimal treatment strategies to reduce the economic burden of disease.²⁸

Even incremental reductions in intraocular pressure (IOP) can be significant from the health economic standpoint. In a study using a cost-offset model to analyse the clinical and economic outcomes of lowering IOP, an extra 1mmHg of IOP reduction accounted for fewer cases of progression and increased cost savings on office visits, visual field tests, additional glaucoma medications, and surgeries over a seven-year period.²⁹

“According to a US study, there is a fourfold increase in direct ophthalmology-related costs as glaucoma severity increases” 

IOP-Lowering Medications 

The cost-effectiveness of different IOP lowering medications is highly dependent on the cost of such medicines in different health care settings, as well as the overall health care system. However, a substantial body of research has shown that all four classes of medications available in Australia are cost-effective treatment options at various stages of disease.^30-35

Selective Laser Trabeculoplasty

Poor adherence to topical therapy is a well established challenge in the management of glaucoma patients.^36,37

According to the Glaucoma Adherence and Persistency Study, only 10% of patients are continuously persistent with IOP-lowering medications throughout a year.³⁷ In addition, only around half of patients who have a gap in refilling their prescription will re-start their drops, and of these, nearly 80% will have at least another gap.³⁷

Selective laser trabeculoplasty (SLT) is a potential solution to the issue of drop adherence. However, there is a discrepancy in the outcomes of treatment reported in the literature.^38,39 Nevertheless, the LiGHT study demonstrated a 97% probability of laser-first being more cost-effective than medicine-first in the United Kingdom’s National Health Service, with a reduction in ophthalmology costs of ￡458 per patient.⁴⁰ Compared with medication, SLT provided a stable, drop-free IOP control to 74.2% of patients for at least three years, with a reduced need for surgery, lower cost and comparable quality of life measures. However, this analysis would need to be replicated in Australia’s health care system to establish the cost-effectiveness of each treatment option.

Surgery 

The advent of minimally invasive glaucoma surgery (MIGS) has created a potential inflection point in the surgical management of glaucoma. Some of these techniques, in particular trabecular bypass at the time of cataract surgery, have been shown to be cost-effective in different health care systems.^41-43 However, the randomised controlled trials (RCTs) used for the efficacy values in these studies were company sponsored. Therefore, further research is required on the cost-effectiveness of these treatment options in the Australian system.

In addition, we must ensure that all new surgical developments are appropriately tested prior to widespread implementation. A systematic review of MIGS trials showed that only 0.29% of studies were the gold-standard RCT, with the vast majority being retrospective chart reviews or cohort studies, which have significant methodological issues.⁴⁴ The importance of clinical rigour was recently highlighted by a RCT and subsequent cost-effectiveness study on a newly released subconjunctival microstent, which was shown to be economically dominated (i.e. inferior outcomes with higher costs) compared to trabeculectomy.^45,46 Some subconjunctival MIGS currently available in Australia have still not had a single peer-reviewed, published RCT. Although surgical innovation must be incentivised and encouraged, ensuring these novel techniques are safe, effective, and cost-effective is paramount to our practice as eye care providers – both from an economic point of view but also to ensure we provide optimal, evidence-based patient care.

CONCLUSION

Management of glaucoma requires early detection, treatment adherence, quality of life improvement, and advancing medical research. To achieve this, strong collaboration is required between ophthalmologists, optometrists, orthoptists, industry, pharmacists, general practitioners, patient advocacy groups, and funding bodies.

Glaucoma is common, costly, and underdiagnosed – leading to significant visual disability and its associated economic impact. As glaucoma prevalence increases exponentially with age, glaucoma numbers are rising with our rapidly aging population. Both economic and individual costs increase with disease severity. As such, early identification and treatment of patients will reduce the individual burden of disease on quality of life and minimise the associated economic burdens.

“Management of glaucoma requires early detection, treatment adherence, quality of life improvement and advancing medical research”

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