Background: The epidemiology of multiple sclerosis (MS) and neuromyelitis optica (NMO) remains to be clarified or updated in many parts of Asia. This study aims to investigate the epidemiology and comorbidities of MS and NMO during 2001-2015 in Taiwan.
Methods: We conducted a retrospective nationwide population-based study using data from Taiwan's National Health Insurance Research Database. Cases of MS and NMO aged 20 years or above during 2001-2015 were enrolled. The incidence, prevalence, demographic features, and comorbidities were investigated.
Results: We identified 4627 MS and 861 NMO incident cases aged 20 or above during 2003-2015. The incidence of MS was relatively stationary, while that of NMO apparently rose steeply during the study period. The age-standardized incidence rate of MS and NMO in 2015 were 1.34 and 0.61 per 100,000 person-years, respectively. The age-standardized prevalence rate of MS and NMO in 2015 were 6.69 and 1.47 per 100,000 persons, respectively. The female preponderance was evident for both MS and NMO. Except for diabetes mellitus, the most common autoimmune comorbidities for MS and NMO were Sjogren syndrome and systemic sclerosis, and Sjogren syndrome and systemic lupus erythematosus, respectively.
Conclusions: Taiwan has transitioned from low- to medium-risk zone during 2001-2015 in terms of MS prevalence, although its incidence remained stationary. The apparent upsurge of NMO over the period probably reflects increased awareness of this clinical entity. Comorbid autoimmune disorders were relatively common, and overlapping but differential autoimmune comorbidity profiles were noted for MS and NMO.
Keywords: Autoimmune disease; Comorbidity; Epidemiology; Multiple sclerosis; Neuromyelitis optica.
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