Análise de custo-utilidade do tratamento do glaucoma primário de ângulo aberto no Brasil

Abstract

Glaucoma is the main cause of irreversible blindness in the world and in Brazil. The most common type, primary open-angle glaucoma, has genetic basis, therefore primary prevention (avoiding occurrence of the disease) is difficult to perform. Main actions to prevent glaucoma blindness target secondary prevention (early diagnosis and effective treatment). The most important risk factor for glaucoma is ocular hypertension. In glaucomatous patients, intra-ocular pressure elevates as aqueous humor outflow pathways (trabecular meshwork) are progressively obstructed. Glaucoma treatment involves medications, laser or surgery. As world population grows and becomes older, both incidence and prevalence of primary open-angle glaucoma tend to be higher in the future. Hence, there is an urgent need for a costeffective resource allocation in order to reducing its economic impact. The purpose of this study is to determine the most cost-effective strategy for the treatment of primary open-angle glaucoma in Brazil. Participants were a hypothetical cohort of primary open-angle glaucoma patients, separated into early, moderate and advanced stages. We developed 3 Markov models (one for each glaucoma stage), from the perspective of the Brazilian Public Health System and a horizon of the average life expectancy of the Brazilian population. We tested different strategies for each model. Main outcome measures were incremental cost-utility ratio, medical direct costs and quality-adjusted life year. The results show that in early glaucoma, incremental cost-utility ratio of initial laser and initial medical treatment over observation only, were R$2.811,39/QALY (Quality-adjusted life year) and R$3.450,47/QALY, respectively. Both strategies were cost-effective. The two alternatives have provided significant gains in quality of life over no treatment. In moderate glaucoma, both laser and surgery were highly cost-effective. Initial medical therapy in this group led to higher costs and was marginally cost-effective. For advanced glaucoma patients, both surgery and medications were cost-effective. In all models, starting age had a great impact on results. Both laser and surgery were more cost-effective, the younger the patient. In conclusion, from early to advanced glaucoma, all tested treatment strategies were cost-effective and provided real gains in quality of life. We suggest different strategies for different glaucoma stages, according to a cost-effectiveness ratio ranking.