The epidemiology and burden of neuromyelitis optica spectrum disorder, multiple sclerosis, and MOG antibody-associated disease in a province in Thailand: A population-based study

Background: Central nervous system inflammatory demyelinating diseases (CNSIDDs) have notable interracial heterogeneity. The epidemiology of CNSIDDs in Thailand, a mainland Southeast Asian country, is unknown.Objectives: To determine the cumulative incidence, point prevalence, and disease burden of neuromyelitis optica spectrum disorder (NMOSD) and other CNSIDDs in Thailand using population-based data of Chumphon.Methods: Searching for CNSIDD patients at a public secondary care hospital in Chumphon, the only neurology center in the province, from January 2016 to December 2021 was implemented using relevant ICD-10-CM codes. All diagnoses were individually ascertained by a retrospective chart review. Cumulative incidence, point prev-alence, attack rate, mortality rate, and disability-adjusted life years (DALYs) were calculated.Results: Aquaporin 4-IgG-positive NMOSD was the most prevalent CNSIDD in the Thai population at 3.08 (1.76-5.38) per 100,000 persons. The prevalence of multiple sclerosis (MS) followed at 0.77 (0.26-2.26) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) at 0.51(0.14-1.87) per 100,000 adults. In the pediatric population, the incidence of acute disseminated encephalomyelitis was 0.28 (0.08-1.02) per 100,000 persons/year. Among other idiopathic demyelinating diseases, idiopathic optic neuritis had the highest incidence at 0.58 (0.24-0.92) per 100,000 persons/year, followed by acute transverse myelitis at 0.44 (0.14-0.74). Idiopathic demyelinating brainstem syndrome was also observed at 0.04 (0.01-0.25) per 100,000 persons/year. Although most had a fair recovery, disability was worst among NMOSD patients with DALYs of 3.61 (3.00-4.36) years per 100,000 persons. Mortality rate was the highest in NMOSD as well.Conclusion: CNSIDDs are rare diseases in Thailand. The prevalence is comparable to that of East Asian pop-ulations. A nationwide CNSIDDs registry would better elaborate the epidemiology of these diseases.