Prevalence of neuromyelitis optica spectrum disorder in Fujian, China, 2021-2023: a population-based study

Neuromyelitis optica spectrum disorder (NMOSD) is a rare demyelinating autoimmune disease, and data on the prevalence of NMOSD in mainland China are lacking. The goal of this study was to estimate the prevalence of NMOSD in Fujian, China, and to investigate demographic and clinical characteristics.

We conducted a retrospective study using data from the social health insurance database of Fujian Province, which covers nearly all medical institutions in Fujian and 38.33 million insured residents. NMOSD Cases from January 1, 2021 to December 31, 2023 were identified to calculate period prevalence. The crude prevalence was calculated overall and stratified by age group and sex, and was then age- and sex-standardized to the Chinese population.

A total of 515 patients with NMOSD, identified using ICD-10 code G36.0, were found among the insured individuals. The overall crude prevalence was 1.34 per 100,000. The age- and sex-standardized prevalence for the Chinese population was 1.35 per 100,000. The female-to-male prevalence ratio was 4.76:1. Fifty-four (10.5%) patients had concomitant autoimmune diseases. Sixty-seven patients were further investigated, with a median age at onset of 40 (range 10.5-67.5) years. The anti-aquaporin-4 antibody positivity was 74.6%. Fifty-four (80.6%) patients had a relapsing disease course.

This study provides population-based prevalence data for NMOSD in Fujian, China, during the period from 2021 to 2023, representing one of the most up-to-date estimates of NMOSD prevalence in southeastern China. The extrapolated national prevalence may provide valuable insights into the national disease burden of NMOSD in China.