Yen-Pin Chiang

OBJECTIVE: Diabetic retinopathy, which leads to macular edema and retinal neovascularization, is the leading cause of blindness among working-age Americans. Previous research has demonstrated significant cost savings associated with detection of eye disease in Americans with type I diabetes. However, detection and treatment of eye disease among those with type II diabetes was previously thought not to be cost-saving. Our purpose was to estimate the current and potential federal savings resulting from the screening and treatment of retinopathy in patients with type II diabetes, based on recently available data concerning efficacy of treating both macular edema and neovascularization along with new data on federal budgetary costs of blindness. RESEARCH DESIGN AND METHODS: We used computer modeling, incorporating data from population-based epidemiological studies and multicenter clinical trials. Monte Carlo simulation was used, combined with sensitivity analysis and present value analysis of cost savings. RESULTS: Screening and treatment for eye disease in patients with type II diabetes generates annual savings of $247.9 million to the federal budget and 53,986 person-years of sight, even at current suboptimal (60%) levels of care. If all patients with type II diabetes receive recommended care, the predicted net savings (discounted at 5%) exceeds $472.1 million and 94,304 person-years of sight. Nearly all savings are associated with detection and treatment of diabetic macular edema. Enrolling each additional person with type II diabetes into currently recommended ophthalmological care results in an average net savings of $975/person, even if all costs of care are borne by the federal government. CONCLUSIONS: Our analysis indicates that prevention programs aimed at improving eye care for patients with diabetes not only reduce needless vision loss but also will provide a financial return on the investment of public funds.

Major challenges in the evaluation of the "end results" of health services include ensuring that concepts are correctly defined and measured, that the validity of measures used in different applications and populations is well documented, and that observed effects can be clearly interpreted. Health status is the most widely interpretable concept to apply in the context of health services. Quality of life connotes inclusion of the environment outside the context of the person and of health care and may or may not be health related, depending on the evaluation context and the impact of disease and treatment. All concepts and constructs must be defined in reference to their theoretical origin and to a model of relationships among different concepts. Modern test theory offers the potential for individualized, comparable assessments and for the careful examination and application of different measurement models. Selection and critique of measures should be based on the intended application and accumulated evidence for that application. Thus, there are no valid instruments per se. Validity in use, including responsiveness, interpretation of effects, and generalizability to diverse populations, is the most important measurement characteristic for treatment effectiveness. An evaluation of the validity of preference-based measures is particularly important for the interpretation and comparability of outcomes in cost-effectiveness evaluations. The successful translation of research into policy and practice is limited by the extent to which these critical issues are addressed in actual treatment evaluations.

BACKGROUND: Retinopathy of prematurity (ROP) is the leading cause of blindness among premature infants. A recent National Eye Institute-sponsored prospective, multicenter trial investigating the use of cryotherapy for treatment of ROP demonstrates a significant reduction in blindness and low vision for patients with sight-threatening (stage 3+) ROP. METHOD: A microsimulation model is presented to determine the cost-effectiveness of cryotherapy for ROP. Simulations are performed for three subpopulations of premature infants with birth weights 500 through 749 g, 750 through 999 g, and 1000 through 1249 g, and for three screening strategies--weekly, biweekly, and monthly. RESULTS: Appropriately timed screening for and treatment of ROP is predicted to result in a gain of 3899 to 4648 quality-adjusted-life-years and a net governmental budgetary savings of $38.3 to $64.9 million for each annual US birth cohort of 28,321 premature infants (500 through 1249 g). The cost per quality-adjusted-life-year gained is $2488 to $6045, depending on different screening strategies. CONCLUSIONS: Of greatest importance is the finding that properly timed screening and treatment for ROP is not only cost saving but may save approximately 320 infants per year from a lifetime of blindness.

Federal expenditures for blindness-related disability among Americans are examined. The government, rather than the private sector, frequently bears the economic consequences of visual disability through entitlement and public assistance programs. Findings suggest an average $11,896 federal cost of a person-year of blindness for a working-aged American, which includes income assistance programs (SSDI/SSI), health insurance programs (Medicare/Medicaid), and tax losses resulting from reduced potential earnings. Almost 97 percent of the aggregate annual federal costs of blindness in 1990, which totaled approximately $4 billion, is accounted for by working-aged adults, who represent less than one-third of the total blind population. Approximately 25 percent of all blindness is attributed to preventable causes.