The prevalence and characteristics of neuromyelitis optica in Japan: A nationwide epidemiological study

Dynamic changes in patient admission and their disabilities in multiple sclerosis and neuromyelitis optica: A Japanese nationwide administrative data study

BACKGROUND

The real-world data evidences how establishment of neuromyelitis optica (NMO) disease concept and development disease modifying therapy affect the patients with multiple sclerosis (MS) and NMO are lacking. The aim of this study is to clarify the diachronic trend of the severity and admissions of patients with MS and NMO.

METHODS

We retrospectively investigated the trends in admissions, treatments, and disabilities in the patients with MS and NMO using the Japanese administrative data between 2012 and 2017.

RESULTS

We analyzed acute stage 9545 and 2035 admissions in each 6100 MS and 1555 NMO patients. The annual number of admission in MS significantly decreased in 6 years; however, those in NMO consistently increased. The patient proportion with lower disability was significantly increased in MS and NMO. These trends were especially observed in patients admitted to centralized hospitals with more active treatments, such as second-line disease modifying therapy for MS and plasmapheresis for NMO. Patients with NMO using DMT for MS diminished in 6 years.

CONCLUSION

A gradual improvement of disability in patients with MS and NMO was observed, probably due to advanced treatments, increased NMO awareness, and decreased misdiagnosis, which seems to be the key for better prognosis in MS and NMO.

Worldwide prevalence of neuromyelitis optica spectrum disorder (NMOSD) and neuromyelitis optica (NMO): a systematic review and meta-analysis

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a progressive demyelinating disease of the central nervous system that has overlapping symptoms with multiple sclerosis (MS) but differs from it in a variety of ways. Previous studies have reported conflicting results trying to estimate the number of individuals affected by them which is why we designed this systematic review and meta-analysis to estimate the worldwide prevalence and incidence of NMOSD/NMO based on current evidence.

METHODS

We searched PubMed, Scopus, EMBASE, Web of Science, and gray literature including references from the identified studies, review studies, and conference abstracts which were published up to February 1, 2022. We used all MeSH terms pertaining to "NMOSD," "NMO," and all the terms on "prevalence," "incidence," and "epidemiology" to identify the search components. Pooled effect sizes were measured using random-effect model by DerSimonian-Laird.

RESULTS

The prevalence and incidence rates of NMOSD/NMO ranged from 0.07 to 10 and 0.029 to 0.880 per 100,000 population, respectively. The overall pooled prevalence of NMO per 100,000 population was 1.54 (I²: 98.4%, 95% CI: 1.13-1.96, P< 0.001) based on the 2006 criteria, 1.51 (I²: 99.4%, 95% CI: 1.21-1.81, P < 0.001) based on the 2015 criteria and 2.16 (I²: 89.4%, 95% CI: 1.46-2.86, P < 0.001) based on the 2006/2015 criteria. The overall annual incidence of NMO per 100,000 population was 0.155 (I²: 95%, 95% CI: 0.115-0.195, P < 0.001) based on the 2006 criteria and 0.278 (I²: 100%, 95% CI: 0.135-0.420, P < 0.001) based on the 2015 criteria. The prevalence rates were highest in French West Indies and South Korea, and lowest in Cuba and Australia, based on the 2006 and 2015 criteria, respectively. Also, the highest annual incidence rates were obtained for Sweden and Slovak republic and the lowest for Cuba and Australia based on the 2006 and 2015 criteria, respectively. All estimated rates were higher among females compared to males.

CONCLUSION

Although rare, NMOSD/NMO impact affected individuals in devastating ways. Several large-scale prospective studies are required to reach a comprehension of the epidemiological aspects of these notorious demyelinating conditions.

Prevalence and Incidence of Neuromyelitis Optica Spectrum Disorder in Korea: Population Based Study

BACKGROUND

Although neuromyelitis optica spectrum disorder (NMOSD) is known to be a rare disease, its prevalence and incidence have not yet been studied in Korea. We performed a population-based study to examine the prevalence and incidence of NMOSD in Korea using data from the Korean National Health Insurance (NHI) claims database.

METHODS

Data from 2013 to 2017 were obtained, with a washout period set as 2013 and 2014. The prevalence and incidence of NMOSD in 2016 and 2017 were calculated using population census data. Subjects were divided into 5 groups at 15-year intervals, depending on the age at which the diagnostic code was entered. The relative risk (RR) for each age group was compared with the oldest (≥ 60 years) age group.

RESULTS

The overall prevalence was estimated to be 3.36 and 3.56 per 100,000 individuals, with an incidence of 0.41 and 0.65 per 100,000 individuals-year in 2016 and 2017, respectively. The mean age was 43.08 (standard deviation, 14.56) years, and the ratio of male to females was 1:4.7. The incidence was higher in female individuals aged between 30 and 59 years (RR, 2.8-3.05; P < 0.05).

CONCLUSION

Nationwide prevalence of NMOSD in Korea was 3.36 and 3.56/100,000 and its incidence was 0.41 and 0.65/100,000-year in 2016 and 2017 respectively.