Nationwide epidemiological study of neuromyelitis optica spectrum disorder in Serbia.

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease of the central nervous system, mediated by antibodies against aquaporin 4 (AQP4-IgG) in 80 % of cases. The aim of the study was to estimate the prevalence of NMOSD and incidence over a twelve-year study period (2013-2024), in Serbia.

METHODS

This study comprises data from 146 NMOSD patients, diagnosed according to the NMOSD criteria 2015. Data were collected in such a way that neurologists from all five university hospitals in Serbia, sent data for each newly diagnosed patient, immediately after diagnosis, to the Registry. In this investigation, incidence of both NMOSD and AQP4-IgG positive NMOSD was calculated between January 1, 2013 and December 31, 2024. The prevalence day was December 31, 2024.

RESULTS

A total of 146 cases were included in this investigation (115 incident; 124 prevalent; 22 died). The study population provided a total 64,251,000 person-years of observation and 115 incident patients from 2013 to 2024. The crude incidence rate of NMOSD diagnosis was 1.79 (95 % Confidence interval-CI 1.11-2.74) per million person-years for both sexes. On the prevalence day, the crude prevalence for the total NMOSD Serbian cohort was 2.32/100,000 (0.86/100,000 in males and 3.66/100,000 in females). Regarding AQP4-IgG positive NMOSD patients, the crude prevalence was 2.02/100,000, and the crude incidence rate 1.42/1000,000. The crude disease-specific mortality was 0.23 (95 %CI 0.13-0.38) per million person-years. The SMR was 1.64 (95 %CI 1.05-2.44).

CONCLUSION

NMOSD incidence and prevalence in Serbia was similar to the existing data in White people. The risk of death in our NMOSD patients was higher than in the general population.