Abstract
Abstract: :
Purpose: OHTS demonstrated the effectiveness of topical ocular hypotensive medication in delaying or preventing the onset of primary open angle glaucoma (POAG). This report provides a preliminary estimate of cost-effectiveness of treatment of persons over age 40 with IOP > 24 mm Hg (OH), and identifies thresholds of utility loss and POAG incidence that may define cost-effectiveness of treatment. Methods: We modeled treating 100,000 persons with OH, similar to OHTS participants in demographic characteristics, for 20 years. Model parameters were estimated using OHTS data and the literature (see Table). Effectiveness was defined as years of POAG and blindness prevented, weighted by the loss of utility (a measure of quality of life). Incidence of POAG was varied to estimate its impact on cost-effectiveness. Loss of quality of life due to POAG was modeled as .01 (least utility loss) to .1 (most loss). Blindness was defined as corrected visual acuity of 20/200 or worse in the best eye. Discount rates of 0%, 3% and 7% were used. Cost-utility ratios representing the cost per quality-adjusted life year (QALY) gained are reported. Results: Assuming a 1.9% annual incidence of POAG (as was found in OHTS), treating all persons with OH yields an estimated cost of $97,355 per QALY gained (i.e., not cost-effective), at a utility loss of .01. Assuming a higher utility loss of .05, treatment was cost-effective ($47,130/QALY). Assuming a higher incidence of POAG (i.e., 4.0%), cost-effectiveness was achieved at a low utility loss of .01 (i.e., $48,886/QALY). The discount rate had no effect on outcome. Conclusions: A cost/QALY of less than $50,000 is widely regarded as defining a cost-effective treatment. Given this standard, treatment of all persons with OH to prevent POAG is not cost-effective unless POAG has substantial impact on quality of life. However, the model suggests that treatment of persons with risk factors in addition to OH that increase risk of POAG may be cost-effective. Further investigation to identify such risk factors and the impact on glaucoma on a person's quality of life is needed.
Keywords: clinical (human) or epidemiologic studies: hea • intraocular pressure