PEE8: FOUR YEAR COST-EFFECTIVENESS OF INITIAL TRABECULECTOMY VERSUS CONVENTIONAL THERAPY IN PRIMARY OPEN-ANGLE GLAUCOMA (POAG)

Abstract

OBJECTIVES: To determine the cost-effectiveness of the primary treatment of primary open-angle glaucoma (POAG) with trabeculectomy versus conventional therapy. METHODS: A four-year incremental cost/quality-adjusted life year (QALY) model (year 2000 US dollars) of POAG using a societal perspective; including direct and indirect costs with a 3% annual discount rate for the base case. In the Glasgow trial, patients newly diagnosed with POAG with an intraocular pressure of 26mmHg and/or with glaucomatous field defects were randomized to trabeculectomy or conventional therapy (up to three medications). In the trabeculectomy branch, patients would either be 1) controlled without extra medication, 2) controlled with extra medication or 3) die from natural causes. Annual chance nodes for the conventional were 1) controlled by medication, 2) surgery or 3) death from natural causes. QALYs were calculated assuming a decline in utility would accompany loss in visual field. A 65-year old patient with a 5% rate of decline in utility was used as the base case. Sensitivity analyses were performed on the rate of utility decline, cost of medications, trabeculectomy cost, and discount rate. RESULTS: For the base case, the cost of initial trabeculectomy was $8316 versus $6339 for conventional therapy. The incremental cost was $1977 and the incremental QALY was 0.08, with ICE ratio of $24,830/QALY. CONCLUSIONS: Initial trabeculectomy is cost-effective for POAG. The model was most sensitive to the rate of decline in utility (<2%) and robust to changes in the costs of medications and trabeculectomy. Limitations include the lack of long-term clinical and QALY data on glaucoma patients with different treatments. Currently the standard of practice in the US is to start with conventional therapy for patients with moderate or severe glaucoma. Our results indicate that trabeculectomy may be a cost-effective option for these patients.