Incidence and prevalence of neuromyelitis optica spectrum disorders in Slovakia

Objective : Neuromyelitis optica spectrum disorders (NMOSDs) are a group of rare, inflammatory, demyelinating diseases that affect the central nervous system. Neither the incidence nor the prevalence of NMOSD has been determined in Slovakia thus far. The aim of this study was to determine both the incidence and the prevalence of NMOSD in Slovakia using the 2015 International Panel of NMOSD diagnosis (IPND) criteria. Methods : We performed a population-based study in Slovakia to estimate both the incidence and the prevalence of NMOSD during the period from 1 January 2006 through 31 December 2019. NMOSD cases were reported from multiple sources and the diagnosis was subsequently verified using the IPND criteria by a joint commitee of three neurologists. The prevalence is reported as number of cases per 100,000 inhabitans and the incidence as number of new cases per 1,000,000 person-years. Age-adjusted rates to the WHO standard population 2005-2025 were also calculated. Results : We identified 63 NMOSD cases. The crude point-prevalence rate was 1.37 (95% CI 1.03-1.71) per 100,000 inhabitants. The crude indidence rate was 0.88 (95% CI 0.65-1.12) per 1,000,000 person-years. The age-adjusted point-prevalence rate was 1.42 (95% CI 1.07-1.84) per 100,000 persons and the age-adjusted incidence rate was 0.96 (95% CI 0.72-1.25) per 1,000,000 person-years. Conclusion : The NMOSD epidemiological situation in Slovakia is comparable to those reported from other Caucasian populations.