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Neuromyelitis optica spectrum disorders: A nationwide Portuguese clinical epidemiological study

Ernestina Santos, Ana Luísa Rocha, Vanessa Oliveira, Daniela Ferro, Raquel Samões, Ana Paula Sousa, Sónia Figueiroa, Teresa Mendonça, Pedro Abreu, Joana Guimarães, Raquel Sousa, Cláudia Melo, Inês Correia, Joao Durães, Lívia Sousa, João Ferreira, João de Sá, Filipa Sousa, Marta Sequeira, Ana Sofia Correia, Ana Luísa André, Carlos Basílio, Marta Arenga, Irene Mendes, Inês Brás Marques, Sandra Perdigão, Helena Felgueiras, Ivânia Alves, Filipe Correia, Cândida Barroso, Armando Morganho, Cátia Carmona, Filipe Palavra, Mariana Santos, Vasco Salgado, Adelaide Palos, Hipólito Nzwalo, Angela Timóteo, Rui Guerreiro, Luís Isidoro, Daniela Boleixa, Paula Carneiro, Esmeralda Neves, Ana Martins Silva, Guilherme Gonçalves, Maria Isabel Leite, Maria José Sá

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PMID: 34583213 DOI: 10.1016/j.msard.2021.103258


Introduction: Neuromyelitis optica spectrum disorder (NMOSD) is a rare disorder in which astrocyte damage and/or demyelination often cause severe neurological deficits.

Objective: To identify Portuguese patients with NMOSD and assess their epidemiological/clinical characteristics.

Methods: This was a nationwide multicenter study. Twenty-four Portuguese adult and 3 neuropediatric centers following NMOSD patients were included.

Results: A total of 180 patients met the 2015 Wingerchuk NMOSD criteria, 77 were AQP4-antibody positive (Abs+), 67 MOG-Abs+, and 36 seronegative. Point prevalence on December 31, 2018 was 1.71/100,000 for NMOSD, 0.71/100,000 for AQP4-Abs+, 0.65/100,000 for MOG-Abs+, and 0.35/100,000 for seronegative NMOSD. A total of 44 new NMOSD cases were identified during the two-year study period (11 AQP4-Abs+, 27 MOG-Abs+, and 6 seronegative). The annual incidence rate in that period was 0.21/100,000 person-years for NMOSD, 0.05/100,000 for AQP4-Abs+, 0.13/100,000 for MOG-Abs+, and 0.03/100,000 for seronegative NMOSD. AQP4-Abs+ predominated in females and was associated with autoimmune disorders. Frequently presented with myelitis. Area postrema syndrome was exclusive of this subtype, and associated with higher morbidity/mortality than other forms of NMOSD. MOG-Ab+ more often presented with optic neuritis, required less immunosuppression, and had better outcome.

Conclusion: Epidemiological/clinical NMOSD profiles in the Portuguese population are similar to other European countries.

Keywords: Clinical; Epidemiological; Neuromyelitis optica spectrum disorders; Portugal.