Epidemiology of pediatric multiple sclerosis, neuromyelitis optica, and optic neuritis in Taiwan

Sex ratio and age of onset in AQP4 antibody-associated NMOSD: a review and meta-analysis

BACKGROUND

Aquaporin-4 (AQP4) antibody-associated neuromyelitis optica spectrum disorder (NMOSD) is an antibody-mediated inflammatory disease of the central nervous system. We have undertaken a systematic review and meta-analysis to ascertain the sex ratio and mean age of onset for AQP4 antibody associated NMOSD. We have also explored factors that impact on these demographic data.

METHODS

A systematic search of databases was conducted according to the PRISMA guidelines. Articles reporting sex distribution and age of onset for AQP4 antibody-associated NMSOD were reviewed. An initially inclusive approach involving exploration with regression meta-analysis was followed by an analysis of just AQP4 antibody positive cases.

RESULTS

A total of 528 articles were screened to yield 89 articles covering 19,415 individuals from 88 population samples. The female:male sex ratio was significantly influenced by the proportion of AQP4 antibody positive cases in the samples studied (p < 0.001). For AQP4 antibody-positive cases the overall estimate of the sex ratio was 8.89 (95% CI 7.78-10.15). For paediatric populations the estimate was 5.68 (95% CI 4.01-8.03) and for late-onset cases, it was 5.48 (95% CI 4.10-7.33). The mean age of onset was significantly associated with the mean life expectancy of the population sampled (p < 0.001). The mean age of onset for AQP4 antibody-positive cases in long-lived populations was 41.7 years versus 33.3 years in the remainder.

CONCLUSIONS

The female:male sex ratio and the mean age of onset of AQP4 antibody-associated NMOSD are significantly higher than MS. The sex ratio increases with the proportion of cases that are positive for AQP4 antibodies and the mean age of onset increases with population life expectancy.

Impact of comorbidities on relapsing rates of Neuromyelitis Optica Spectrum Disorders: Insights from a longitudinal study in Taiwan

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory demyelinating disease characterized by relapsing clinical episodes and the presence of autoantibodies. The impact of comorbidities on relapsing rate of NMOSD patients in Taiwan remains unclear.

METHODS

We conducted a longitudinal retrospective study using the largest hospital system in Taiwan from 2006 to 2021. Demographic characteristics, annualized relapse rates (ARR), and comorbidities were examined.

RESULTS

We identified 485 NMOSD patients from 2006 to 2021. Of these, 466 had the adult form and 19 (3.9 %) had the pediatric form of NMOSD. The median ARR was 0.51 (interquartile range (IQR): 0.26-1.11) for adults and 0.39 (IQR: 0.21-0.77) for pediatric patients. Comorbidities included malignancy (6.7 %) and autoimmune diseases (21.7 %). The recommended age for malignancy surveillance in NMOSD patients was 43.3 years. Neither malignancy nor autoimmune disease increased the ARR within 3 years post diagnosis in NMOSD patients with comorbidities compared with those without comorbidities.

CONCLUSIONS

Our study revealed the ARR within the initial three years after diagnosis was significantly higher, emphasizing the importance of early treatment. We also observed an association between malignancy and NMOSD, and a significantly higher risk of malignancy in adult patients with NMOSD than in the general population (the relative risk was 5.99) that requiring further investigations into the underlying mechanisms. These findings contribute to a better understanding of NMOSD and its comorbidities in Taiwan.

Epidemiology and distribution of 207 rare diseases in China: A systematic literature review

Epidemiological data on rare diseases in China are currently limited. The objective of this study was to provide a comprehensive understanding of the prevalence and incidence of rare diseases by systematically analyzing the available epidemiological data. We conducted a comprehensive search of English and Chinese databases, the Incidence and Prevalence Database, the Chinese Rare Disease Guideline, and the Taiwan Health Promotion Administration from 2010 to 2023. We identified the top diseases and regions based on epidemiological data and present the maximum, minimum, and median prevalence and incidence values in tables and forest plots. 1,264 prevalence and incidence data were retrieved from 277 studies, guidelines and official websites, covering 110 rare diseases (53.1%) and 32 regions (94.1%). In terms of geographical regions, incidence or prevalence data were available for 32 regions (94.1%), excluding Tibet Hui Autonomous Region and Macao Special Administrative Region. In terms of rate, 60 and 77 out of 207 diseases (29.0% and 37.2%) had available incidence and prevalence data, respectively. Eight diseases had an incidence rate equal to or greater than that of 1,000 patients per million. The present study provides a comprehensive epidemiological analysis and valuable insights into the prevalence and incidence of rare diseases in China. Our findings underscore the pressing need for sustained drug research and medical support for individuals and families impacted by rare diseases.

Epidemiology and Healthcare Utilization in Pediatric Multiple Sclerosis and Neuromyelitis Optica: A Nationwide Population-Based Study in South Korea (2016-2020)

Pediatric multiple sclerosis (MS) and neuromyelitis optica (NMO) are rare acquired demyelinating syndrome with limited epidemiological data available, particularly in non-Western setting. This study aimed to demonstrate the epidemiology of pediatric MS and NMO in South Korea and to analyze of healthcare utilization and economic burden associated with these conditions. Using a nationwide population-based database from the Korean Health Insurance Review and Assessment Service database, we identified pediatric cases (age < 20 years) of MS and NMO from 2016 to 2020. We analyzed incidence, prevalence, healthcare utilization and medical costs. The study found low age-standardized incidence and prevalence rates for pediatric MS and NMO in South Korea. There was a marked disparity in healthcare utilization between urban and rural areas. Most healthcare interactions occurred in tertiary hospitals in urban settings, particularly in Seoul. The study also highlighted the substantial economic burden associated with the management of rare diseases, with annual variability in medical costs. Pediatric MS and NMO are extremely rare in South Korea, with significant regional disparity in healthcare utilization. The findings emphasize the need for targeted healthcare policies to improve access and reduce disparities, particularly for chronic and rare diseases requiring specialized care.

Characteristics of Optic Neuritis in South Korean Children and Adolescents: A Retrospective Multicenter Study

Purpose

To analyze the clinical characteristics and prognosis of optic neuritis (ON) in pediatric patients aged <19 years in South Korea.

Methods

This multicenter retrospective cohort study included 127 pediatric patients (median age: 10.3 (IQR: 7.3–14.2) years; female, 62.2%) who experienced ON for the first time between January 2004 and January 2018, with data obtained from five tertiary university-based hospitals in Korea. When ON was bilateral, the worse eye was selected for analysis. The baseline clinical characteristics and prognoses of patients, as well as the associations between these parameters, were analyzed.

Results

The baseline clinical characteristics of the patients were as follows: best-corrected visual acuity (BCVA) < 20/200, 65.9%; pain on eye movement, 47.2%; optic disc swelling, 66.9%; and bilateral involvement, 41.7%. Among 101 patients who were followed up for ≥6 months, 48 (47.5%), 12 (11.9%), 19 (18.8%), 13 (12.9%), and 9 (8.9%) had been diagnosed with isolated ON, recurrent ON, multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and acute disseminated encephalomyelitis (ADEM)-related ON, respectively. At the latest visit, 81.9% and 71.1% had achieved BCVA of ≥20/40 and ≥ 20/25, respectively. Only disc swelling at presentation was associated with poor baseline BCVA (coefficient: 0.31, P=0.004) and greater improvement in BCVA (coefficient: 0.49, P = 0.001P=0.001); there were no significant associations between the baseline factors and final BCVA.

Conclusions

This study demonstrated pediatric ON-related clinical characteristics and visual outcomes in South Korea. Within this cohort, in about 40.6% of patients, ON was associated with other demyelinating diseases, namely, MS, NMOSD, and ADEM.

[Epidemiology of neuromyelitis optica spectrum disorder]

Neuromyelitis optica spectrum disorder (NMOSD) is a group of rare and mostly severe autoimmune demyelinating central nervous system disorders which prevalence is 0.7-1 per 100.000 population and incidence is 0.037-0.73 per 100.000 person-years. NMOSD may present as a combination of uni- or bilateral optic neuritis, transverse myelitis or lesions of brain stem and other brain regions. The symptoms are mostly relapsing (up to 97.5%) and progressive. Occurrence of relapses is associated with seropositivity for aquaporin-4 (up to 80% of NMOSD patients) and bears a less favorable prognosis (mortality up to 32%). Women seropositive for aquaporin 4 constitute 90% of NMOSD patients. Compared to other demyelinating disorders, NMOSD is characterized by late onset (mean age is about 39 years) and association with other autoimmune disorders, including systemic lupus erythematosus, myasthenia gravis and Sjogren's syndrome. A genetic predisposition was found among Blacks and Asians, with HLA-DRB1*03:01 gene associated with higher risk of NMOSD in Asians. The course of the disease tends to be more severe in Blacks. There are clusters of an increased incidence of NMOSD in the Carribeans and in the Far East. Continued increase of prevalence and incidence of NMOSD worldwide compels continued epidemiological research in order to provide early diagnosis and treatment for this disorder.

Multiple sclerosis epidemiology in Asia and Oceania; A systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) is an inflammatory demyelinating CNS disease and the most common neurological immune-mediated disorder. Due to its progressive format, it affects patients' quality of life (QoL) significantly. This study aimed to evaluate epidemiologic parameters of MS in the Asia and Oceania continents.

METHODS

A comprehensive literature search on October 1st, 2020, was performed in PubMed, Scopus, and Web of Science to retrieve original population-based studies on MS epidemiology in the Asian and Oceanian countries, published between January 1st, 1985 and October 1st, 2020. The designed search strategy was repeated for each country, and the relevant referenced articles were added to our database. A random-effect model was used to combine the epidemiological estimates, and subgroup analysis was also performed by continent, region, and country, when possible. Meta-regression analysis was done to evaluate the effects of Human Developmental Index (HDI), latitude, and study period on the epidemiologic parameters.

RESULTS

A total of 3,109 publications were found, of which 89 articles met the eligibility criteria and were included for data extraction. These articles provided data on prevalence, incidence, and mean age at disease onset in 18 countries in Asia and Oceania, including Iran, Turkey, Cyprus, Kuwait, Saudi Arabia, Qatar, UAE, Jordan, Israel, India, Malaysia, China, Hong Kong, Taiwan, Republic of Korea, Japan, Australia, and New Zealand. The pooled total prevalence, incidence, and mean age of onset in Asia and Oceania were 37.89/100000 (95% CI: 35.65 - 40.142), 2.40/100000 (95% CI: 2.22 - 2.58), and 28.21 (95% CI: 27.55 - 28.88), respectively. MS prevalence and incidence in the female gender (68.7/100000 and 4.42/100000, respectively) were infinitely higher than in the male gender (24.52/100000 and 2.06/100000, respectively). Our subgroup analysis showed that MS was much more prevalent in Australia and West Asia among the studied area. The meta-regression showed that the total incidence decreased with an increase in the HDI, and the total prevalence in Asia increased with increasing latitude gradients. Also, the study period had a positive effect on the total prevalence and incidence in Asia and Oceania.

CONCLUSION

MS prevalence and incidence have increased in recent decades. This study highlights the need for further studies to elucidate MS's geographical and temporal variations' exact etiologies.

Safety and outcome of mechanical thrombectomy in ischaemic stroke related to carotid artery dissection

BACKGROUND

The net clinical benefit of mechanical thrombectomy (MT) in patients with anterior circulation ischaemic stroke associated with large vessel occlusion (AIS-LVO) related to carotid artery dissection (CAD) is uncertain. The aim of the study was to investigate the safety and clinical outcomes of patients treated by MT for a CAD-related stroke.

METHODS

We included consecutive patients with AIS-LVO treated by MT between 1st 2015 and January 1st 2020 at Lille University Hospital. We compared the safety and clinical outcomes, including successful recanalisation, defined as a modified thrombolysis in cerebral infarction (mTICI) ≥ 2b and favourable functional outcome at 3 months (defined as a modified Rankin Scale (mRS) ≤ 2 or equal to pre-stroke), in patients with CAD-related stroke versus patients with other aetiologies.

RESULTS

We included 1422 patients, among them, 43 patients with CAD-related AIS-LVO were matched to 86 patients with other aetiologies. Procedural complications, sICH (ECASS-3 criteria) and mortality rates were similar in the two groups (OR 0.85, 95% CI 0.21-3.49, p = 0.82; OR 1.54 95% CI 0.33-2.79, p = 0.58; OR 0.18 95% CI 0.02-1.46, p = 0.11, respectively), as well as the rates of intracranial angiographic successful recanalisation and favourable functional outcome (OR 0.67 (95% CI 0.26-1.73, p = 0.41; OR 1.26 (95% CI 0.61-2.64, p = 0.53). In patients with CAD-related stroke, intracranial angiographic success after MT was significantly associated with favourable functional outcome.

CONCLUSIONS

In patients with AIS-LVO related to CAD, safety profiles and clinical outcomes after MT are similar compared to matched patients with other stroke aetiologies.

Epidemiology of Demyelinating Diseases in Korean Pediatric Patients

The epidemiology of demyelinating diseases in the Korean pediatric population has not been reported to date. This study aimed to identify the epidemiology of demyelinating diseases in Korean children by using big data. The subjects were children (0-17 years old) diagnosed with acute-disseminated encephalomyelitis, multiple sclerosis, neuromyelitis optica, and Guillain-Barré syndrome enrolled in the Korean Health Insurance Review and Assessment Service (HIRA) from January 2010 to December 2017.Of 1722 enrolled children, 553 (32.1%) had acute-disseminated encephalomyelitis, 170 (9.9%) had multiple sclerosis, 68 (3.9%) had neuromyelitis optica, and 931 (54.1%) had Guillain-Barré syndrome. The male-female ratios were 1.47:1 in acute-disseminated encephalomyelitis, 1.43:1 in Guillain-Barré syndrome, 1:1.66 in multiple sclerosis, and 1:1.62 in neuromyelitis optica. Demyelinating diseases were most prevalent in summer. The prevalence differed by region, with 545 (31.6%) in Seoul and 298 (17.3%) in Gyeonggi. This study is the first to identify the incidence of demyelinating diseases in South Korea.

Epidemiology of Neuromyelitis Optica Spectrum Disorder and Its Prevalence and Incidence Worldwide

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon inflammatory disease of the central nervous system, manifesting clinically as optic neuritis, myelitis, and certain brain and brainstem syndromes. Cases clinically diagnosed as NMOSD may include aquaporin 4 (AQP4)-antibody-seropositive autoimmune astrocytopathic disease, myelin oligodendrocyte glycoprotein (MOG)-antibody-seropositive inflammatory demyelinating disease, and double-seronegative disease. AQP4-antibody disease has a high female-to-male ratio (up to 9:1), and its mean age at onset of ~40 years is later than that seen in multiple sclerosis. For MOG-antibody disease, its gender ratio is closer to 1:1, and it is more common in children than in adults. Its clinical phenotypes differ but overlap with those of AQP4-antibody disease and include acute disseminated encephalomyelitis, brainstem and cerebral cortical encephalitis, as well as optic neuritis and myelitis. Double-seronegative disease requires further research and clarification. Population-based studies over the past two decades report the prevalence and incidence of NMOSD in different populations worldwide. One relevant finding is the varying prevalence observed in different racial groups. Consistently, the prevalence of NMOSD among Whites is ~1/100,000 population, with an annual incidence of <1/million population. Among East Asians, the prevalence is higher, at ~3.5/100,000 population, while the prevalence in Blacks may be up to 10/100,000 population. For MOG-antibody disease, hospital-based studies largely do not observe any significant racial preponderance so far. This disorder comprises a significant proportion of NMOSD cases that are AQP4-antibody-seronegative. A recent Dutch nationwide study reported the annual incidence of MOG-antibody disease as 1.6/million population (adult: 1.3/million, children: 3.1/million). Clinical and radiological differences between AQP4-antibody and MOG-antibody associated diseases have led to interest in the revisions of NMOSD definition and expanded stratification based on detection of a specific autoantibody biomarker. More population-based studies in different geographical regions and racial groups will be useful to further inform the prevalence and incidence of NMOSD and their antibody-specific subgroups. Accessibility to AQP4-antibody and MOG-antibody testing, which is limited in many centers, is a challenge to overcome. Environmental and genetic studies will be useful accompaniments to identify other potential pathogenetic factors and specific biomarkers in NMOSD.