Uso da memantina na doença de Alzheimer grave: análise de custo-efetividade na perspectiva do Sistema Único de Saúde.

Abstract

Alzheimer's disease (AD) represents the most common cause of dementia, being a progressive and incurable neurodegenerative disease, expressed by a variety of neuropsychiatric symptoms. It the main responsible for mortality rates and functional dependence among the elderly, representing an economic impact important for families and universal health systems. Although the literature observes that the effects of memantine on AD are small, the drug was incorporated into the Brazilian Health System in 2017. However, contrary to the legal norm regarding the incorporation of technologies in SUS, this process was not accompanied by an economic evaluation that would demonstrate the cost-effectiveness of this drug. This study examined the cost-utility of memantine for severe AD compared to no specific pharmacological treatment, from the perspective of the SUS as a care funder. A systematic review of economic evaluation studies using memantine alone or in combination with donepezil for moderate to severe AD has been conducted. The review allowed to know the state of the art of economic evaluations and made it possible to raise general aspects related to the modeling used in the studies to assist in the construction of the analytical decision model conducted in the cost-effectiveness study. A Markov model was constructed to model the progression of AD based on the severity states of AD (mild, moderate and severe), defined by the MEEM, plus the dead state. Cycles of 1 year were considered and the adopted time horizon was 5 years. The costs of memantine were considered for 2 years, but the effects observed only during the first year. Costs and benefits were discounted at 5%. Compared with no specific treatment, memantine represented an increase in care costs and gains in QALY. Patients who used memantine had a gain 3,080 QALY over the simulated 5 years at an incremental cost of $ 351.500,00 and an ICER of $ 114.205,75 in amounts already discounted for the reference case. The results found are difficult to compare with studies conducted outside the country. If the cost-effectiveness threshold adopted in Brazil was previously recommended by the WHO, memantine would be considered a non-cost-effective technology based on the analysis of the reference case. In this way, its incorporation would not be justified in the national context, given its high costs and a small benefit and circumscribed to the time.