A esclerectomia profunda não penetrante como forma de prevenção secundária da cegueira pelo glaucoma e seu impacto na saúde coletiva: um estudo de custo-efetividade

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 very difficult to perform. Main actions to prevent glaucoma blindness are targeted to secondary prevention (early diagnosis and effective treatment). The most important risk factor for glaucoma is ocular hypertension. In glaucomatous patients, intra-ocular pressure (IOP) becomes elevated as aqueous humor outflow pathways (trabecular meshwork) is progressively and partially obstructed. Glaucoma treatment involves medications, laser or surgery. Among different surgical techniques, non-penetrating deep sclerectomy (NPDS) appears as a viable alternative to classical trabeculectomy. Its purposes are: controlling IOP and improving safety by reducing intra and post-operative complications. As world population grows and becomes older, both incidence and prevalence of glaucoma are expected to be higher in the future. Hence there is an urgent need for a cost-effective resource allocation in order to reducing its economic impact. The aim of this study is to evaluate the impact of NPDS in public health in Brazil, as a secondary prevention tool, through an analysis of its results (effectiveness and complications) and through the calculation of cost-effectiveness relationship in a consecutive retrospective case series of 228 operated eyes in a 5-year follow-up period. This result was compared to the cost-effectiveness of medical therapy using prostaglandin analogues alone or in combination with Timolol 0.5% or Cosopt. NPDS presented success rates compared to those found in literature (68.42% for IOP < 18 mmHg without medication) with few complications. Most frequent complication was fibrosis of the filtering bleb (20.6%), which was comparable to previous studies. Cost to reduce the IOP in 1% in 5 years was R$ 28.54 for NPDS. The same cost for medications varied from R$ 58.65 to R$ 129.85. NPDS can provide to the Brazilian Public Health System (SUS) an economy up to 78.02 % when compared to medications in 5 years. The impacts of these results are analyzed and discussed.