Health economics, economic evaluation, and glaucoma

Is primary trabeculectomy cost-effective for patients with advanced primary open angle glaucoma? Results from the Treatment of Advanced Glaucoma Study economic model

BACKGROUND/AIMS

Advanced primary open angle glaucoma (POAG) is a lifelong condition. The aim of this study is to compare medical treatment against trabeculectomy for patients presenting with advanced POAG using an economic evaluation decision model.

METHODS

A Markov model was used to compare the two treatments, medical treatment versus trabeculectomy for the management of advanced POAG, in terms of costs and quality-adjusted life-years (QALYs). The uncertainty surrounding the model findings was assessed using probabilistic sensitivity analysis and deterministic analysis. Data for the model came from Treatment of Advanced Glaucoma Study supplemented with data from the literature. The main outcomes of the model presented in terms of Incremental costs and QALYs based on responses to the EQ-5D-5L, Health Utilities Index-3 and a Glaucoma Utility Index.

RESULTS

In the base-case analysis (lifetime horizon and EQ-5D-5L measure), participants receiving trabeculectomy had on average, an additional cost of £2687, an additional 0.28 QALYs and an incremental cost per QALY of £9679 compared with medical treatment. There was a 73% likelihood of trabeculectomy being considered cost-effective when society was willing to pay £20 000 for a QALY. Over shorter time horizons, the incremental cost per QALY gained from trabeculectomy compared with medical treatment was higher (47 663) for a 2-year time horizon. Our results are robust to changes in the key assumptions and input parameters values.

CONCLUSION

In patients presenting with advanced POAG, trabeculectomy has a higher probability of being cost-effective over a patient's lifetime compared with medical treatment.

Primary trabeculectomy versus primary glaucoma eye drops for newly diagnosed advanced glaucoma: TAGS RCT

BACKGROUND

Patients diagnosed with advanced primary open-angle glaucoma are at a high risk of lifetime blindness. Uncertainty exists about whether primary medical management (glaucoma eye drops) or primary surgical treatment (augmented trabeculectomy) provide the best and safest patient outcomes.

OBJECTIVES

To compare primary medical management with primary surgical treatment (augmented trabeculectomy) in patients with primary open-angle glaucoma presenting with advanced disease in terms of health-related quality of life, clinical effectiveness, safety and cost-effectiveness.

DESIGN

This was a two-arm, parallel, multicentre, pragmatic randomised controlled trial.

SETTING

Secondary care eye services.

PARTICIPANTS

Adult patients presenting with advanced primary open-angle glaucoma in at least one eye, as defined by the Hodapp-Parrish-Anderson classification of severe glaucoma.

INTERVENTION

Primary medical treatment - escalating medical management with glaucoma eye drops. Primary trabeculectomy treatment - trabeculectomy augmented with mitomycin C.

MAIN OUTCOME MEASURES

The primary outcome was health-related quality of life measured with the Visual Function Questionnaire-25 at 2 years post randomisation. Secondary outcomes were mean intraocular pressure; EQ-5D-5L; Health Utilities Index 3; Glaucoma Utility Index; cost and cost-effectiveness; generic, vision-specific and disease-specific health-related quality of life; clinical effectiveness; and safety.

RESULTS

A total of 453 participants were recruited. The mean age of the participants was 67 years (standard deviation 12 years) in the trabeculectomy arm and 68 years (standard deviation 12 years) in the medical management arm. Over 65% of participants were male and more than 80% were white. At 24 months, the mean difference in Visual Function Questionnaire-25 score was 1.06 (95% confidence interval -1.32 to 3.43; p = 0.383). There was no evidence of a difference between arms in the EQ-5D-5L score, the Health Utilities Index or the Glaucoma Utility Index. At 24 months, the mean intraocular pressure was 12.40 mmHg in the trabeculectomy arm and 15.07 mmHg in the medical management arm (mean difference -2.75 mmHg, 95% confidence interval -3.84 to -1.66 mmHg; p < 0.001). Fewer types of glaucoma eye drops were required in the trabeculectomy arm. LogMAR visual acuity was slightly better in the medical management arm (mean difference 0.07, 95% confidence interval 0.02 to 0.11; p = 0.006) than in the trabeculectomy arm. There was no evidence of difference in safety between the two arms. A discrete choice experiment updated the utility values for the Glaucoma Utility Index. The within-trial economic analysis found a small increase in the mean EQ-5D-5L score (0.04) and that trabeculectomy has a higher probability of being cost-effective than medical management. The incremental cost of trabeculectomy per quality-adjusted life-year was £45,456. Therefore, at 2 years, surgery is unlikely to be considered cost-effective at a threshold of £20,000 per quality-adjusted life-year. When extrapolated over a patient's lifetime in a model-based analysis, trabeculectomy, compared with medical treatment, was associated with higher costs (average £2687), a larger number of quality-adjusted life-years (average 0.28) and higher incremental cost per quality-adjusted life-year gained (average £9679). The likelihood of trabeculectomy being cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life year gained was 73%.

CONCLUSIONS

Our results suggested that there was no difference between treatment arms in health-related quality of life, as measured with the Visual Function Questionnaire-25 at 24 months. Intraocular pressure was better controlled in the trabeculectomy arm, and this may reduce visual field progression. Modelling over the patient's lifetime suggests that trabeculectomy may be cost-effective over the range of values of society's willingness to pay for a quality-adjusted life-year.

FUTURE WORK

Further follow-up of participants will allow us to estimate the long-term differences of disease progression, patient experience and cost-effectiveness.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN56878850.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 72. See the NIHR Journals Library website for further project information.

Vision utilities in Italy and the United States: Comparison of time tradeoff vision utilities

Background/Aims:

To compare time tradeoff vision utilities from two developed Western countries to ascertain whether these vision-related, quality-of-life preferences are similar.

Methods:

Time tradeoff utilities were acquired from ophthalmology patient populations with ophthalmic pathologic conditions by personal interview in Italy and the United States using a reliable and previously validated, standardized questionnaire.

Results:

Data from 47 consecutive Italian participants and 325 consecutive American participants were compared. The populations were matched for gender, age, and ophthalmic pathologic conditions. The utilities for the various vision sub-cohort levels, characterized according to vision in the better-seeing eye for the Italian/American cohorts were as follows: (1) 20/20 sub-cohort, Italian/American mean utilities = 0.82/0.91 (p = 0.10); (2) 20/25–20/30 sub-cohort, Italian/American mean utilities = 0.79/0.86, (p = 0.05); (3) 2040–20/100 sub-cohort, Italian/American mean utilities = 0.76/0.74 (p = 0.70); and (4) 20/200 or less sub-cohort, Italian/American mean utilities = 0.66/0.58 (p = 0.58).

Conclusion:

Vision-related quality of life, as measured by time tradeoff utilities, was similar in Italian and American ophthalmic populations. This information is relevant when comparing quality of life and cost-utility analyses across international borders.

Health technology assessment: A primer for ophthalmology

Rising healthcare costs and increasing demands for health care require techniques to choose between competing uses and even rationing of health care. Economic evaluations and health technology assessments are increasingly a means to assess the cost effectiveness of healthcare interventions so as to inform such resource allocation decisions. To date, the adoption of health technology assessments, as a way of assessing cost effectiveness, in ophthalmology has been slower, relative to their implementation in other specialities. Nevertheless, demands for eye services are increasing due to an ageing population. The prevalence of conditions such as glaucoma, cataract, diabetic eye disease and age-related macular degeneration increases with age, and it is predicted that global blindness will triple by 2050. So there is a challenge for ophthalmologists to ensure that they can contribute to, interpret, critically evaluate, and use findings from economic evaluations in their clinical practice. To aid this, this article serves as a primer on the use of health technology assessments to assess cost effectiveness using economic evaluation techniques for ophthalmologists. Healthcare systems face many challenges worldwide – changing demographics and evolution of new technologies are only going to intensify. With this in mind, ophthalmology needs to be ready and able to engage with health economists to prepare, interpret, critically evaluate and use findings of economic evaluations and health technology assessments.

Type 2 diabetes in Vietnam: a cross-sectional, prevalence-based cost-of-illness study

BACKGROUND

According to the International Diabetes Federation, total global health care expenditures for diabetes tripled between 2003 and 2013 because of increases in the number of people with diabetes as well as in the average expenditures per patient. This study aims to provide accurate and timely information about the economic impacts of type 2 diabetes mellitus (T2DM) in Vietnam.

METHOD

The cost-of-illness estimates followed a prospective, prevalence-based approach from the societal perspective of T2DM with 392 selected diabetic patients who received treatment from a public hospital in Ho Chi Minh City, Vietnam, during the 2016 fiscal year.

RESULTS

In this study, the annual cost per patient estimate was US $246.10 (95% CI 228.3, 267.2) for 392 patients, which accounted for about 12% (95% CI 11, 13) of the gross domestic product per capita in 2017. That includes US $127.30, US $34.40 and US $84.40 for direct medical costs, direct nonmedical expenditures, and indirect costs, respectively. The cost of pharmaceuticals accounted for the bulk of total expenditures in our study (27.5% of total costs and 53.2% of direct medical costs). A bootstrap analysis showed that female patients had a higher cost of treatment than men at US $48.90 (95% CI 3.1, 95.0); those who received insulin and oral antidiabetics (OAD) also had a statistically significant higher cost of treatment compared to those receiving OAD, US $445.90 (95% CI 181.2, 690.6). The Gradient Boosting Regression (Ensemble method) and Lasso Regression (Generalized Linear Models) were determined to be the best models to predict the cost of T2DM (R2=65.3, mean square error [MSE]=0.94; and R2=64.75, MSE=0.96, respectively).

CONCLUSION

The findings of this study serve as a reference for policy decision making in diabetes management as well as adjustment of costs for patients in order to reduce the economic impact of the disease.

Frequency of visual field testing when monitoring patients newly diagnosed with glaucoma: mixed methods and modelling

Background

Visual field (VF) tests are the benchmark for detecting and monitoring the eye disease glaucoma. Measurements from VF tests are variable, which means that frequent monitoring, perhaps over a long period of time, is required to accurately detect true glaucomatous progression. In 2009, guidelines for the diagnosis and management of glaucoma issued by the National Institute for Health and Care Excellence revealed an absence of research evidence about the clinical effectiveness and cost-effectiveness of using different monitoring intervals to detect disease progression. However, the European Glaucoma Society (EGS) guidelines on patient examination recommend that newly diagnosed glaucoma patients should undergo VF testing three times per year in the first 2 years after initial diagnosis.

Objectives

The primary objective of this project was to explore the clinical effectiveness and cost-effectiveness of using different monitoring intervals to detect VF progression in newly diagnosed glaucoma patients. Other objectives sought to (1) explore glaucoma patients’ views and experiences of monitoring using focus groups; and (2) establish glaucoma subspecialists’ attitudes regarding frequency of VF testing using a five-item questionnaire.

Design

These questions were investigated using a multicentre audit of current practice and existing NHS data (VF records from almost 90,000 patients). New research knowledge was provided through statistical and health economic modelling of these and additional published data.

Results

The multicentre audit showed that VF monitoring is, on average, carried out annually. Patient focus groups indicated that, although patients do not like VF testing, they accept it as a critical part of their care. Patients raised concerns regarding distracting testing environments, quality of instructions, explanation of results and excessive waiting times. Questionnaires revealed that clinicians’ attitudes towards the frequency of VF testing varied considerably, and many glaucoma specialists believed that current recommendations are impractical. Statistical modelling suggested that EGS recommendations could be clinically effective as progression can be identified sooner than is possible with annual testing. Health economic modelling suggested that increased VF monitoring may also be cost-effective [incremental cost-effectiveness ratio (ICER) was equal to £21,679].

Conclusions

Statistical modelling of VF data suggests there is strong rationale for following EGS recommendations with the primary benefit of providing better information about fast-progressing patients. Our health economic model suggested that increasing VF testingmaybe cost-effective (ICER was equal to £21,679), especially when accounting for gains to society. Nevertheless, many clinicians consider increased VF testing of patients impossible with current resources. In addition, patient focus groups raised concerns about the practicalities of delivery of VF tests.

Future work

Results from this study could inform the design of a prospective randomised comparative trial of different VF monitoring intervals in glaucoma linked to stratifying patients according to risk factors for progression. The statistical model for VF data can be further developed to be used as a practical tool for optimising individualised follow-up. The views of clinicians and patients indicate that service delivery of VF testing is an important issue and worthy of further investigation. Ensuring the confidence and co-operation of the patient should be at the centre of future research into the most efficient strategies for glaucoma monitoring.

Funding

This work was funded by the National Institute for Health Research Health Services and Delivery Research programme.

Comparison of resource utilization in the treatment of open-angle glaucoma between two cities in Finland: is more better?

INTRODUCTION

Glaucoma is a progressive optic neuropathy associated with neural rim loss of the optic disc and the retinal nerve fibre layer typically causing visual field (VF) deterioration. Generally, glaucomatous lesions in the eye and in the visual field progress slowly over the years. In population-based cross-sectional studies, the percentage of unilateral or bilateral visual impairment varied between 3-12%. In screening studies, 0.03-2.4% of patients have been found to suffer visual impairment. Glaucoma has previously been associated with substantial healthcare costs and resource consumption attributable to the treatment of the disease. The disease also causes reduction in health-related quality of life (HRQoL) in patients with glaucoma.

OBJECTIVE AND METHODS

This study compares patients with diagnosed open-angle glaucoma from two geographically different regions in Finland. A total of 168 patients were examined, 85 subjects from an area with higher per patient treatment costs (Oulu) and 83 patients from a region with lower per patient treatment costs (Turku). All patients had a history of continuous glaucoma medication use for a period of 11 years. For each patient, the total direct costs from glaucoma treatment were calculated and the total amount of resource consumption was determined from registries and patient records. Each patient underwent a clinical examination with visual field assessment and fundus photography. These data were used to determine the current stage of disease for each patient. Health-related quality of life questionnaire (15D) was used in determining each patient's subjective HRQoL score.

RESULTS

When applying the current diagnostic criteria for open-angle glaucoma, a total of 40% of patients did not to display any structural or functional damage suggesting glaucoma after 11 years of continuous medical treatment and follow-up. Patients with higher glaucoma stage (worse disease) were found to have statistically higher treatment costs compared with those at lower disease stages. Resource consumption was also greater in the patients in higher glaucoma stage. Patients in the Oulu district consumed more resources, and glaucoma treatment was more expensive than in the Turku area. The total treatment cost in Oulu and Turku was 6010 € and 4452 €, respectively, for the whole 11-year period. There was no statistically significant difference in quality-of-life scores between the two areas. No difference was noted between the higher-spending and lower-spending areas in this respect. However, when the population was analysed as a whole, patients with higher glaucoma stage were found to have lower vision-based 15D scores compared with those at lower disease stages. This observation was made also at both districts independently.

CONCLUSIONS

Major cost source in open-angle glaucoma treatment is medication, up to 74% of annual costs. In addition, it seems that higher resource consumption and higher treatment costs do not increase the patients' HRQoL as assessed by the 15D instrument.

Cost-effectiveness of screening for open angle glaucoma in developed countries

As all developed countries are struggling with health care costs growing too large and too fast, the current performance and overburden of glaucoma services demand a reappraisal of current management strategies. The performance of the glaucoma care in western countries offers several opportunities to improve the simultaneous under- and over-diagnosis and treatment. Since available resources are finite, they should be targeted to produce the best eye health. There is an obvious need for prioritization of all interventions, including improving case finding. The limited evidence to date indicates that we do not have enough evidence to decide whether systematic population screening could be cost-effective in the developed world. This article gives an overview of the methods of economic evaluation and the evidence on cost-effectiveness of systematic screening for glaucoma in the developed world, need for future research and challenges related to evaluation of increasing economic literature as well as need to change behaviors on the basis of evidence.

Safety, tolerability, and efficacy of fixed combination therapy with dorzolamide hydrochloride 2% and timolol maleate 0.5% in glaucoma and ocular hypertension

Glaucoma is a collection of diseases characterized by multifactorial progressive changes leading to visual field loss and optic neuropathy most frequently due to elevated intraocular pressure (IOP). The goal of treatment is the lowering of the IOP to prevent additional optic nerve damage. Treatment usually begins with topical pharmacological agents as monotherapy, progresses to combination therapy with agents from up to 4 different classes of IOP-lowering medications, and then proceeds to laser or incisional surgical modalities for refractory cases. The fixed combination therapy with the carbonic anhydrase inhibitor dorzolamide hydrochloride 2% and the beta blocker timolol maleate 0.5% is now available in a generic formulation for the treatment of patients who have not responded sufficiently to monotherapy with beta adrenergic blockers. In pre- and postmarketing clinical studies, the fixed combination dorzolamide–timolol has been shown to be safe and efficacious, and well tolerated by patients. The fixed combination dorzolamide–timolol is convenient for patients, reduces their dosing regimen with the goal of increasing their compliance, reduces the effects of “washout” when instilling multiple drops, and reduces the preservative burden by reducing the number of drops administered per day.

Modeling complex treatment strategies: construction and validation of a discrete event simulation model for glaucoma

OBJECTIVE

Discrete event simulation (DES) modeling has several advantages over simpler modeling techniques in health economics, such as increased flexibility and the ability to model complex systems. Nevertheless, these benefits may come at the cost of reduced transparency, which may compromise the model's face validity and credibility. We aimed to produce a transparent report on the construction and validation of a DES model using a recently developed model of ocular hypertension and glaucoma.

METHODS

Current evidence of associations between prognostic factors and disease progression in ocular hypertension and glaucoma was translated into DES model elements. The model was extended to simulate treatment decisions and effects. Utility and costs were linked to disease status and treatment, and clinical and health economic outcomes were defined. The model was validated at several levels. The soundness of design and the plausibility of input estimates were evaluated in interdisciplinary meetings (face validity). Individual patients were traced throughout the simulation under a multitude of model settings to debug the model, and the model was run with a variety of extreme scenarios to compare the outcomes with prior expectations (internal validity). Finally, several intermediate (clinical) outcomes of the model were compared with those observed in experimental or observational studies (external validity) and the feasibility of evaluating hypothetical treatment strategies was tested.

RESULTS

The model performed well in all validity tests. Analyses of hypothetical treatment strategies took about 30 minutes per cohort and lead to plausible health-economic outcomes.

CONCLUSION

There is added value of DES models in complex treatment strategies such as glaucoma. Achieving transparency in model structure and outcomes may require some effort in reporting and validating the model, but it is feasible.

Healthcare charges in patients with glaucoma who undergo laser trabeculoplasty

INTRODUCTION

The objective of this study was to assess the impact of laser trabeculoplasty (LTP) on healthcare charges in patients with primary open-angle glaucoma (POAG).

METHODS

Using a managed care database (PharMetrics; Watertown, MA, USA), we formed a case-control group nested within a POAG cohort (n=72,412) formed using International Classification of Disease, Ninth Edition (ICD-9) coding data. Cases (n=1145) had LTP (Current Procedural Terminology code: 65855) with ≥1 year of continuous enrollment both prior to, and following LTP index date in PharMetrics from 1998-2005. Using the date of LTP as the index date, controls (n=2290) without LTP were matched to cases on gender, age, and index year in a 2:1 ratio. Cases and controls had ≥6 months of continuous enrollment in PharMetrics prior to receiving a diagnosis of POAG (ICD-9 code: 365.11). One-year total and ophthalmology healthcare charges were calculated in the year pre- and post-index date (excluding charges for LTP at the index date). Conditional logistic regression models and multiple linear regression models determined the impact of LTP on healthcare charges, while controlling for glaucoma duration and other key covariates.

RESULTS

While the mean age of cases (60.1±13.1 years) and controls (60.3±13.6 years) was similar (P=0.5589), cases had more comorbid systemic conditions (P<0.05) and underwent more cataract surgery in the year after index date (4.4% vs. 2.1%; P=0.002). In the year after index date, ophthalmology-related charges increased by $1364 for cases vs. $30 for controls (P=0.0003). Total healthcare charges increased by $5084 for cases and $1594 for controls in the year after index date (P=0.0085). Cases and controls experienced similar increases in ophthalmology-related pharmacy charges from the year pre- to the year post-index date ($26 vs. $43, P=0.385). In both logistic regression and linear regression models, which adjusted for several covariates, performing LTP was associated with increased total healthcare and ophthalmology-related charges.

CONCLUSION

Among patients with POAG in this study, performing LTP was associated with increased total and ophthalmology-related healthcare charges, while ophthalmology pharmacy charges did not decline.

The need and total cost of Finnish eyecare services: a simulation model for 2005-2040

PURPOSE

The aims of this study were: (i) to create a structural simulation model capable of predicting the future need and cost of eyecare services in Finland; and (ii) to test and rank different policy alternatives for access to care and the required physician workforce.

METHODS

Using the system dynamics approach, the number and cost of patients with cataract, glaucoma, diabetic retinopathy and age-related macular degeneration (AMD) were described with causal-loop diagrams and were then translated into a set of mathematical equations to build a computer simulation model. Mathematically, the problem was formulated as a set of differential equations that were solved numerically with specialized software. The validity of the model was tested against prevalence and administrative historical data. The costs covered by the public sector in Finland were obtained from 2003 from the Finnish Hospital Discharge Register (including outpatient care), the Finnish Social Insurance Institution and a survey of hospital price lists. Different levels of access to public care were then simulated in four eye diseases, for which the model estimated the need for services and resources and their costs in the years 2005-2040.

RESULTS

The model forecasted that the adoption of the 2005 national 'access to care' criteria for cataract surgery would shorten waiting lists. If the workload of Finnish ophthalmologists were kept at the 2003 level, the graduation rate of new ophthalmologists would have to increase by 75% from the current level. If all glaucoma patients were followed in the public sector in future, even this increase in training would not meet the demand for physician workforce. The current model indicated that the screening frequency of diabetes can be increased without large sacrifices in terms of costs. AMD therapy has a significant role in the allocation of future resources in eyecare. The modelling study predicted that ageing alone will increase the costs of eyecare during the next four decades in Finland by about 1% per year in real terms (undiscounted and without inflation of unit costs). The increases in total yearly costs were on average 8.6% between 2001 and 2003.

CONCLUSIONS

The results of this modelling study indicate that policy initiatives, such as defining criteria for access to care, can have substantial implications on the demand for care and waiting times whereas the effect of ageing alone was relatively small. Measures to control several other factors - such as the adoption and price level of new technologies, treatments and practice patterns - will be at least equally important in order to restrain healthcare costs effectively.

Estimated first-year costs of prostaglandin analogs with/without adjunctive therapy for glaucoma management: a United States perspective

OBJECTIVE

To evaluate costs associated with prostaglandin analogs among newly-diagnosed glaucoma patients in a managed-care population.

RESEARCH DESIGN AND METHODS

A cost minimization model compared annual costs for patients initiating therapy with one of the three prostaglandin analogs (bimatoprost, latanoprost, travoprost). The study cohort was identified from pharmacy claims and eligibility files of patients who met study inclusion criteria. Annual costs were estimated for patients initiating therapy with each prostaglandin based on treatment patterns and medication use over the year. Costs for outpatient physician visits and medications were estimated from standard sources.

RESULTS

A total of 4444 patients met study criteria: 674 received travoprost, 729 received bimatoprost, and 3041 received latanoprost. More than 80% stayed on monotherapy for 1 year (82.9% of travoprost patients, 82.8% of bimatoprost patients, and 80.5% of latanoprost patients). Of those who required adjunctive therapy, the average number of days until starting adjunctive therapy was 130 days for travoprost patients, 94 days for bimatoprost patients, and 104 days for latanoprost patients. Average annual costs were $1198, $1290, and $1217 for patients treated with travoprost, bimatoprost, and latanoprost, respectively.

CONCLUSIONS

The use of adjunctive therapy in glaucoma is an important driver of glaucoma management costs. This study demonstrates that the longer duration of monotherapy and the likelihood to use single rather than combination adjunctive agents contribute to lower annual costs among patients starting on travoprost compared with the other available prostaglandin analogs. Study limitations include the lack of clinical indicators in the study database; further, results may not be generalizable to patients who discontinue prostaglandin analogs or to the population of patients with glaucoma as a whole. Future studies with clinical and compliance indicators would further identify distinctions among treatment regimens.

Glaucoma in the United States and europe: predicting costs and surgical rates based upon stage of disease

PURPOSE

Primary open-angle glaucoma is a significant health-economic burden in both the United States and Europe that is likely to increase. This study compared treatment patterns and cost among patients with primary open-angle glaucoma in these locations.

METHODS

Retrospective medical chart reviews were conducted in the United States (1990 to 2002) and Europe (1995 to 2003). A total sample of 151 US charts and 194 European charts was studied, and patients were assigned a baseline intraocular pressure (IOP) and baseline stage, using a 6-stage visual functional glaucoma staging algorithm. Resource utilization and direct costs were assessed by stage of disease using publicly available United States and European costs. Cox Proportional Hazards modeling were used to examine covariates predicting glaucoma surgery. Total cost was predicted, adjusting for covariates using Generalized Linear Models, with baseline stage as the independent variable.

RESULTS

Glaucoma surgery requirement was highly associated with baseline disease stage and IOP increase before surgery in the United States and somewhat associated with these factors in Europe. Within both locations, baseline IOP was highly associated with glaucoma surgery requirement. Controlling for covariates, patients at higher baseline stages incurred greater costs in the United States (P=0.0017) and Europe (P=0.0715). Surgery and medication were also highly predictive of increased cost (P<0.0001). Cost of care differed greatly between the European countries, with costs lowest in Italy.

CONCLUSIONS

Increases in annual cost were related to higher baseline IOP, higher baseline stage, medication, and surgery. Thus, significant potential savings and reductions in annual healthcare burden are possible if patients are diagnosed and treated at earlier stages of glaucoma.

Cost effectiveness and cost utility of an organized screening programme for glaucoma

PURPOSE

To assess the cost effectiveness and cost utility of an organized screening programme for glaucoma. The previous cost-effectiveness studies of screening show inconsistent results, and the cost utility of screening has not been assessed.

METHODS

An organized screening programme was simulated using Markov modelling in a population aged 50-79 years at 5 year intervals. The programme ended when the subjects reached the age of 80 years. The comparator was opportunistic case finding. The main outcome measures were cases and years of severe visual disability avoided, quality-adjusted life years (QALYs) gained and direct healthcare and non-healthcare costs.

RESULTS

The incremental cost of 1 year of avoided visual disability by screening was euro32 602. The cost of one QALY gained by screening was euro9023 with a discount rate of 5%. During the average 20 year time horizon considered, the cumulative incremental costs of screening in a population of 1 million people would be euro30 million, producing 3360 incremental QALYs and 930 years of avoided visual disability for 701 persons. The results were sensitive to the estimates of several parameters, especially screening cost and specificity of screening tests (96-99% specificity required).

CONCLUSION

An organized screening programme could be a cost-effective strategy especially in older age groups, in which screening is clearly more likely to be acceptable to decision makers at any level in terms of their willingness to pay for a QALY. Modelling includes some uncertainty especially concerning the specificity of diagnostic tests and screening cost.

Cost of patients with primary open-angle glaucoma: a retrospective study of commercial insurance claims data

PURPOSE

Primary open-angle glaucoma (POAG) poses a large burden on eye care resources in the United States. We evaluated the total health care and POAG-specific charges (both pharmacy and nonpharmacy) incurred by patients with POAG using a longitudinal U.S. commercial insurance claims database to determine the relative magnitude of glaucoma care charges to overall health care charges for those patients with glaucoma.

DESIGN

Retrospective cohort design.

PARTICIPANTS

Sixty-four thousand three hundred eighty patients with POAG were identified.

METHODS

Patients with POAG were selected (International Classification of Diseases, 9th Revision code 365.11 on at least 2 encounters) from a managed care claims database. Total health care and POAG-specific charges were calculated. Component charges (pharmacy and nonpharmacy) also were evaluated and the charge per treated person was calculated.

MAIN OUTCOME MEASURE

Health care charges.

RESULTS

The mean total health care charges per person in the first year after initial entry into the database with POAG were $13,404 (standard deviation [SD], $33,987), with a median charge of $5403. The mean POAG-specific charge per person was $1570 (SD, $3428), with a median charge of $840. Pharmacy charges were 25% of the POAG-specific charges. The POAG-specific charges in subsequent years after the initial year decreased by 7% per year, whereas the total health care mean charge increased by 39% per year. Patients aged 65 years and older had significantly higher mean charges for both total health care charges ($16,759 vs. $11,651; P<0.0001) and POAG-specific charges ($1624 vs. $1542; P = 0.0049), for an age-related increase of 44% for total charges and 5% for POAG-specific charges. Overall, POAG-specific mean charges represented 12% of total mean charges in the first year and 8% of total overall mean charges in subsequent years.

CONCLUSIONS

There is a substantial cost burden associated with POAG in a population with commercial insurance, and most of these charges are not pharmacy related.

Cost-effectiveness of early detection and treatment of ocular hypertension and primary open-angle glaucoma by the ophthalmologist

PURPOSE

To determine the most cost-effective case-finding strategy for the ophthalmologist to detect and treat ocular hypertension (OH) and primary open-angle glaucoma (POAG) at an early stage to prevent blindness.

DESIGN

A Markov cost-effectiveness simulation model.

METHODS

Three case-finding strategies are analysed and compared. The simulated cohort consists of all initial patients of at least 40 years old visiting an ophthalmic practice. All patients undergo ophthalmoscopy, but tonometry is routinely performed to: (1) all initial patients, (2) high-risk patients only, or (3) no one. The population characteristics are based on data of 1000 initial patients. Transition probabilities are taken from the literature. The (direct) costs of diagnosis and treatment represent those for the Netherlands. The time-horizon of the model is 20 years. An annual discount rate of 4% is used.

MAIN OUTCOME MEASURES

Costs, proportion of patients becoming blind, years of blindness.

RESULTS

The costliest strategy (1) leads to least blindness. The incremental cost-effectiveness ratio, which shows extra costs per year of vision saved in comparison to the cheapest strategy (3), is lower for strategy (1) than for strategy (2). It amounts to euro1707, not including extra costs due to blindness (eg associated with the use of disability facilities). When such costs exceed euro1707 per patient per year, which is most likely, then strategy (1) becomes cost saving.

CONCLUSION

It is most cost-effective to routinely perform tonometry to all initial ophthalmic patients to prevent blindness due to glaucoma.

Travoprost versus latanoprost combinations in glaucoma: economic evaluation based on visual field deficit progression

OBJECTIVE

Changes in intraocular pressure (IOP) are known to be related to visual field deficit progression, although multiple models of this relationship exist. In addition, visual functioning is known to affect medical costs. The objective of this study was to project visual field deficit progression and subsequent costs based on clinical trial data.

RESEARCH DESIGN AND METHODS

Using data from a randomized, 12-month, double-masked study, we compared the use of a fixed combination of travoprost 0.004%/timolol 0.5% (T/T) versus a fixed combination of latanoprost 0.005%/timolol 0.5% (L/T) on visual field deficit progression and associated costs. We applied published algorithms linking IOP to visual field changes to calculate the likelihood of visual field deterioration by treatment group. Differences in medical care costs were estimated using guideline-recommended practice patterns, Medicare hospital costs, and published estimates of differences in hospitalization by visual functioning.

MAIN OUTCOME MEASURES

Increase in visual field deficit progression rates, increase in annual hospital days per subject, and increase in annual hospital, outpatient, and total costs per subject.

RESULTS

Predicted visual field deficit progression for T/T patients was less than that for L/T patients (not statistically significant). Projected annual medical care costs were 43 dollars lower for T/T vs. L/T patients.

CONCLUSIONS

By applying published algorithms linking IOP to visual field changes, this study projected long-term visual field deficit and associated costs. Use of a fixed travoprost/timolol solution may lead to less long-term visual field deficit progression and lower annual medical care costs than a fixed latanoprost/timolol solution.

DISCUSSION

The use of clinical trial data may limit the applicability of these findings. However, this analysis of direct medical costs only is likely a conservative estimate of the costs associated with visual field deficits.

Cost-effectiveness analysis in glaucoma: what drives utility? Results from a pilot study in Sweden

PURPOSE

To investigate the effect of different levels of visual field defect in glaucoma on utilities and to test if utilities could be assessed using a general questionnaire such as the EQ-5D.

METHODS

A cross-sectional study in 199 patients with ocular hypertension or open-angle glaucoma grouped into 5 severity stages according to visual field defects was performed in 4 specialized ophthalmic centres. Descriptive analysis was performed for the sample and by stage, and the effect of vision loss on utility was investigated with multiple step-wise regression analysis.

RESULTS

The mean age of the sample was 70 and the mean MD in the worse eye was -13.1 dB (SD 10.2). Visual acuity (VA) was 0.63 and 0.87 in the worse and better eye, respectively, and the mean utility was 0.80 (SD 0.23). Utility decreased with increasing glaucomatous damage, ranging from 0.84 for mild disease to 0.72 for severe damage (MD -2.5 to -28.1), but the difference between the groups was not statistically significant when controlling for co-morbidity, except for the most severe stage (p < 0.01). In multiple regression analysis, visual field in the better eye was significantly correlated with utility, and there was an indirect correlation between visual field in the worse eye and utility: the effect of total VA on utility was significant, and MD in the worse eye was correlated with total VA.

CONCLUSIONS

Utility is strongly correlated with overall vision. Our results suggest a relationship between glaucomatous damage and utility, and patients with severe damage have a significantly lower utility. However, this should be further investigated in larger samples that include more patients with moderate-severe bilateral damage.

Glaucoma screening: current trends, economic issues, technology, and challenges

PURPOSE OF REVIEW

Glaucoma is one of the leading causes of irreversible blindness worldwide. Early glaucoma detection and treatment are currently the only known methods for preventing blindness and low vision resulting from this frequently asymptomatic disease.

RECENT FINDINGS

New technologies for detecting early glaucomatous damage are important in diagnosing optic nerve disease, not only in community screening settings but also in clinics. Imaging of the optic nerve head and macula and retinal nerve fiber layer analysis can provide quick, automated, and quantitative measurements in agreement with clinical estimates of optic disc structure and visual function. In the area of perimetry, frequency-doubling technology is a promising and feasible mass-screening method with reasonable sensitivity for detecting visual field loss. Central corneal thickness has emerged as a new risk factor for the development and progression of glaucoma, thereby complicating the role of tonometry and measurement of intraocular pressure as screening parameters for glaucoma. Along with technological advances, strides are also being made with public policy and legislative efforts to bring glaucoma onto the national and global health care agenda. These initiatives incorporate vision-screening goals into national disease prevention programs emphasizing the need for early glaucoma detection and treatment.

SUMMARY

Glaucoma awareness needs to be increased through better education, and compliance with follow-up care needs to be improved to decrease the economic and social costs from glaucoma. In addition, screening models need to be developed that will be effective in developing countries where the risk of blindness from glaucoma is highest.

The Economic Burden of Glaucoma and Ocular Hypertension

This paper reviews the burden and economic consequences of glaucoma upon healthcare systems and patients, especially elderly patients. An extensive review of the literature was conducted, primarily using MEDLINE, but also by examining selected article reference lists, relevant websites and the proceedings of specialised conferences. All relevant articles and documents were analysed. Glaucoma is characterised by destruction of the optic nerve. It is most often a continuous, chronic eye disease and the most frequent diagnosis is primary open angle glaucoma (POAG). POAG is mostly associated with intraocular hypertension which can be delayed by medication, surgery or laser therapy. The prevalence rate of glaucoma is about 1% in the population >50 years of age. The rate increases with age and is higher in Black and Hispanic populations. Glaucoma affects more than 67 million people worldwide. Cost-of-illness studies have shown the importance of this disease, on which more than pound300 million was spent in the UK in 2002. Most of the costs (45%) were associated with direct medical costs, but direct nonmedical costs (20%) and indirect costs (35%) were also not negligible. Recent economic studies have shown a dramatic increase in the number of patients with glaucoma receiving treatment but a reduction in use of surgical procedures to treat the condition, especially as first-line therapy. The greater part of medical expenditure is now on medication, with new, more potent, better tolerated, but more costly drugs replacing older and less expensive medications. Treatment costs are directly related to the severity of disease and the number of different treatments used; they are also negatively correlated with treatment efficacy in reducing intraocular pressure. However, long-term economic benefits that may be associated with use of more potent new drugs (by delaying institutionalisation) have never been documented. Glaucoma screening has also been found not to be cost effective, although these results should be reconsidered in the light of new data.

Reducing intraocular pressure: is surgery better than drugs?

Reducing IOP is presently the evidence based, most accepted and most practised therapeutical approach for glaucoma patients. Currently topical ocular hypotensive medications, with its different classes, as well as filtering surgery (trabeculectomy and non-penetrating glaucoma surgery) are in the forefront of therapeutic modalities for IOP reduction. This article looks at the potential advantages and disadvantages of topical medications versus filtering surgery. It does not directly address the question of initial treatment of glaucoma, or what is the better treatment of glaucoma, as other review articles had, but rather looks in a more specific on the pros and the cons of each in relation to IOP reduction. In other words this article deals with the situation once the decision has been made to reduce IOP.

Assessing the cost-effectiveness of switching from a beta-blocker to latanoprost in the treatment of ocular hypertension

Glaucoma is a pathological condition whose most important risk factor is increased intraocular pressure (IOP). The medical treatment of glaucoma essentially consists of compounds that are able to decrease the IOP. The compounds discussed in this review act in a different way, beta-blockers mainly inhibit the production of aqueous humor, whereas latanoprost decreases the resistance in the outflow channels. beta-Blockers are compounds with a well-known efficacy and safety profile and they are fairly inexpensive. Their systemic and local side effects are mainly cardiovascular and pulmonary adverse events, dry eye and keratopathy. Latanoprost, which has recently been introduced into the market, has been shown to be equally as effective, or better in lowering IOP in patients than timolol, although it is more expensive. Systemic reported side effects are anecdotal; local hyperaemia, keratopathy, hypertrichosis, increased pigmentation of eyelashes and iris, uveitis and cystoid macular oedema have been reported. A comparison of costs reveals that a 1-year therapy with timolol ophthalmic solution starts from 11.00 Euros and can reach 146.00 Euros for the most expensive preservative-free 1-day dispenser packages (approximately 13.5 times higher). For latanoprost once-daily administration, the cost for 1 years therapy is 98.55 Euros, approximately six times higher than generic or brand 0.5% timolol applied twice-daily. What are the factors influencing a change in therapy from beta-blockers to latanoprost? The only good reason is represented by a further deterioration in the visual field. This may occur, despite a significant reduction in IOP, because the reached IOP is not sufficient enough to avoid further deterioration because the patient's work or social activities do not allow a correct daily dosage of the compound (bad compliance); or as a result of treatment suspension, because of the development of systemic and/or local side effects. Changes in therapy must always be related to a failing control of the disease, as any therapeutic modification leading to an increase in the number of visits and additional examinations, consequently enhances the costs.