Epidemiology and comorbidities of adult multiple sclerosis and neuromyelitis optica in Taiwan, 2001–2015

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.

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.

The risk of type 2 diabetes mellitus in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study

BACKGROUND AND OBJECTIVES

An association has been suggested between premorbid type 2 diabetes mellitus (T2DM) and the risk of multiple sclerosis (MS). However, little is known about the risk of developing T2DM in MS and neuromyelitis optica spectrum disorder (NMOSD). This study aimed to determine the T2DM risk in patients with MS and NMSOD.

METHODS

The Korean National Health Insurance Service database was analyzed, and 1,801 and 1,721 adults with MS and NMOSD, respectively, who were free of T2DM between January 2010 and December 2017, were included. Matched controls were selected based on age, sex, and the presence of hypertension and dyslipidemia.

RESULTS

The risk of developing T2DM was 1.54 times higher in NMOSD than in the controls (adjusted hazard ratio [aHR], 95 % confidence interval [CI] = 1.20-1.96). However, increased T2DM risk was not observed in MS (aHR = 1.13, 95 % CI = 0.91-1.42). The T2DM risk in patients with NMOSD was higher in those who received steroid treatment (aHR = 1.77, 95 % CI = 1.36-2.30) but not in those who did not (aHR = 0.59, 95 % CI = 0.24-1.43, p for interaction = 0.02).

DISCUSSION

T2DM risk was increased in NMOSD but not in MS. Administering steroid treatment to patients with NMOSD may increase their T2DM risk.

Recent progress in epidemiology, clinical features, and therapy of multiple sclerosis in China

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system characterized by inflammation, demyelination, and neurodegeneration. It mainly affects young adults, imposing a heavy burden on families and society. The epidemiology, clinical features, and management of MS are distinct among different countries. Although MS is a rare disease in China, there are 1.4 billion people in China, so the total number of MS patients is not small. Because of the lack of specific diagnostic biomarkers for MS, there is a high misdiagnosis rate in China, as in other regions. Due to different genetic backgrounds, the clinical manifestations of MS in Chinese are different from those in the West. Herein, this review aims to summarize the disease comprehensively, including clinical profile and the status of disease-modifying therapies in China based on published population-based observation and cohort studies, and also to compare with data from other countries and regions, thus providing help to develop diagnostic guideline and the novel therapeutic drugs. Meanwhile, we also discuss the problems and challenges we face, specifically for the diagnosis and treatment of MS in the middle- and low-income countries.

Survival and Its Correlates in Multiple Sclerosis Patients under a Universal Health Insurance Program in Taiwan: An 18-Year Nationwide Cohort Study

Despite the global decline in the standardized mortality rate of multiple sclerosis (MS), recent research on MS patient survival, especially in Taiwan, remains limited. This study aimed to investigate survival, mortality causes, and associated factors among MS patients in Taiwan. The Taiwan National Health Insurance Research Database was used as the primary data source, and a Cox proportional hazard model was employed to estimate and analyze factors related to survival. We analyzed data from 1444 MS patients diagnosed between 2000 and 2018. Age at diagnosis was positively correlated with the risk of death. Among the 190 patients who died, the leading causes of disease-related deaths were nervous system diseases (n = 83, 43.68%), followed by respiratory system diseases and certain infectious and parasitic diseases. The 8-, 13-, and 18-year survival rates for MS patients were 0.97, 0.91, and 0.81, respectively. This study highlights that the MS patient's socioeconomic status, environmental factors, comorbidity severity, and related medical variables were not significantly associated with survival.

Clinical analysis of neuromyelitis optica spectrum disease with area postrema syndrome as the initial symptom

OBJECTIVE

The objective of this study was to report and discuss clinical analysis, including the diagnosis and treatment of 4 cases of neuromyelitis optica spectrum disease (NMOSD) with area postrema syndrome (APS) as the first symptom.

METHODS

Four patients with intractable nausea, vomiting, and confirmed NMOSD were included in the final analysis. All of these patients were initially misdiagnosed and mismanaged.

RESULTS

Among the 4 patients, 3 were admitted to the department of gastroenterology at the onset of the disease, and 2 were not correctly diagnosed and treated promptly due to misdiagnosis. Therefore, their symptoms worsened, and they were transferred to Intensive Care Unit (ICU) for life support. No obvious early medulla lesions were found in one patient. One patient was treated with intravenous immunoglobulin, methylprednisolone, and plasma exchange, but there was no significant clinical improvement, after which the disease relapsed during the treatment with low-dose rituximab.

CONCLUSION

The clinical manifestations of NMOSD are complex and diverse, and the initial symptoms, onset age of the patient, and magnetic resonance imaging (MRI) findings can influence the final diagnosis. Early identification of the APS and timely therapy can prevent visual and physical disabilities, even respiratory failure, coma, and cardiac arrest. Therefore, it is necessary to identify specific and sensitive serum and imaging markers for predicting the prognosis and recurrence of the disease.

Prevalence of multiple sclerosis in Guangzhou, China: A population-based case-finding prospective study

BACKGROUND

Multiple sclerosis (MS) is rare in China, and the prevalence previously reported may be biased. Currently, few studies that have investigated the prevalence of MS in China based on the latest diagnostic criteria.

METHODS

Through a population-based survey from August 8, 2021 to December 31, 2021, we calculated the prevalence of multiple sclerosis in 18,676,605 residents of Guangzhou, China. MS patients were identified through the health insurance system of the Guangzhou Health Insurance Bureau, and we surveyed 17 large tertiary hospitals using a case-finding approach. All MS patients were diagnosed according to the 2017 McDonald criteria.

RESULTS

A total of 143 patients in the resident population of Guangzhou were diagnosed with MS, with a crude prevalence of 0.77 per 100,000 (95% confidence interval (CI): 0.65-0.90), and the prevalence was higher in in females (1.14/100,000) than in males (0.44/100,000). The age-adjusted prevalence was 0.92 per 100,000 (95% CI: 0.77-1.10). The prevalence peaked at the age of 25-29 years (2.86/100,000) for both males and females (1.44/100,000 and 4.42/100,000, respectively).

CONCLUSIONS

This is the first study to report the prevalence of MS in Guangzhou, China, according to the criteria. Our study shows that the prevalence of MS in Guangzhou is lower than that in other cities in China.

The causal relationship between neuromyelitis optica spectrum disorder and other autoimmune diseases

Objectives

The coexistence of neuromyelitis optica spectrum disorder (NMOSD) with other autoimmune diseases has been well recognized. However, the causal association between these two conditions has not been fully studied. The etiology and therapies of NMOSD coexisting with autoimmune diseases also need to be elucidated.

Methods

We performed two-sample Mendelian randomization (MR) analysis to examine the causality. Genome-wide association (GWAS) summary data from NMOSD, autoimmune thyroid disease (AITD), systemic lupus erythematosus (SLE), and Sjogren’s syndrome (SS) were used to identify genetic instruments. Causal single-nucleotide polymorphisms (SNPs) were annotated and searched for cis-expression quantitative trait loci (cis-eQTL) data. Pathway enrichment analysis was performed to identify the mechanism of NMOSD coexisting with AITD, SLE, and SS. Potential therapeutic chemicals were searched using the Comparative Toxicogenomics Database.

Results

The MR analysis found that AITD, SLE, and SS were causally associated with NMOSD susceptibility, but not vice versa. Gene Ontology (GO) enrichment analysis revealed that MHC class I-related biological processes and the interferon-gamma-mediated signaling pathway may be involved in the pathogenesis of NMOSD coexisting with AITD, SLE, and SS. A total of 30 chemicals were found which could inhibit the biological function of cis-eQTL genes.

Conclusions

Our findings could help better understand the etiology of NMOSD and provide potential therapeutic targets for patients with coexisting conditions.

The incidence and prevalence, diagnosis, and treatment of multiple sclerosis in China: a narrative review

In 2018, the first list of rare diseases was published by the National Health Council of China, and multiple sclerosis (MS) was included in this list. Since then, the Chinese government and neurologists have made efforts to improve the clinical outcomes of patients with MS. During last few years, the incidence of MS in China was also investigated. The early and accurate diagnosis of MS was improved due to the application and promotion of magnetic resonance imaging and new diagnosis criteria. The market for and medical insurance access to disease-modifying therapies (DMTs) has been greatly accelerated, which has provided more treatment options and improved clinical outcomes for patients with MS, as well as reduced treatment cost. The pattern of MS in China is gradually changing, from delayed to early diagnosis, and from no treatment to treatment with DMTs during remission. This narrative review aimed to summarize an update to the status of MS in China, including incidence and prevalence, diagnosis, and available treatments. This would help to better understand the diagnosis and treatment gap between mainland China and other Asian regions, demonstrating the necessity of accurate diagnosis and optimized treatment of MS in China.

Neuromyelitis Optica Spectrum Disorder: From Basic Research to Clinical Perspectives

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system characterized by relapses and autoimmunity caused by antibodies against the astrocyte water channel protein aquaporin-4. Over the past decade, there have been significant advances in the biologic knowledge of NMOSD, which resulted in the IDENTIFICATION of variable disease phenotypes, biomarkers, and complex inflammatory cascades involved in disease pathogenesis. Ongoing clinical trials are looking at new treatments targeting NMOSD relapses. This review aims to provide an update on recent studies regarding issues related to NMOSD, including the pathophysiology of the disease, the potential use of serum and cerebrospinal fluid cytokines as disease biomarkers, the clinical utilization of ocular coherence tomography, and the comparison of different animal models of NMOSD.

Epidemiological investigation of multiple sclerosis and related medical utilisation in Taiwan

BACKGROUND

The increasing trend in the prevalence of multiple sclerosis (MS) cannot be neglected. Long-term epidemiological investigations of MS patients who have been registered in Taiwan are very scarce.

OBJECTIVE

The aim of this study was to investigate the epidemiology of MS and medical utilisation among MS patients in Taiwan.

METHODS

The National Health Insurance Research Database was used as the source of the research population; the time period investigated was 2001-2015. A descriptive statistical analysis of the number of MS patients was conducted. For newly diagnosed MS patients, the frequencies of emergency visits and hospitalisations and changes in their temporal distributions were calculated.

RESULTS

The standardised incidence of MS peaked at 0.50/100,000 in 2003, and the highest standardised prevalence was 7.14/100,000 in 2015. The highest standardised mortality was 0.11/100,000 in 2015, with an overall mortality rate of 13.34/1000 person-years. The number of annual emergency visits for MS patients peaked at 0.9 ± 3.5 in 2011, and the longest annual length of hospital stays was 19.2 ± 40.1 days in 2001, which decreased to 5.6 ± 23.5 days in 2015.

CONCLUSION

The standardised prevalence of MS steadily increased, and its incidence slightly decreased from 2001 to 2015.

What's new in neuromyelitis optica spectrum disorder treatment?

Optic neuritis, an optic nerve inflammatory disease presenting with acute unilateral or bilateral visual loss, is one of the core symptoms of neuromyelitis optica spectrum disorder (NMOSD). The diagnosis of NMOSD-related optic neuritis is challenging, and it is mainly based on clinical presentation, optical coherence tomography, magnetic resonance imaging scans, and the status of serum aquaporin-4 antibodies. In the pathogenesis, aquaporin-4 antibodies target astrocytes in the optic nerves, spinal cord and some specific regions of the brain eliciting a devastating autoimmune response. Current pharmacological interventions are directed against various steps within the immunological response, notably the terminal complement system, B-cells, and the pro-inflammatory cytokine Interleukin 6 (IL6). Conventional maintenance therapies were off-label uses of the unspecific immunosuppressants azathioprine and mycophenolate mofetil as well as the CD20 specific antibody rituximab and the IL6 receptor specific antibody tocilizumab. Recently, four phase III clinical trials demonstrated the safety and efficacy of the three novel biologics eculizumab, inebilizumab, and satralizumab. These monoclonal antibodies are directed against the complement system, CD19 B-cells and the IL6 receptor, respectively. All three have been approved for NMOSD in the US and several other countries worldwide and thus provide convincing treatment options.

[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.

Burden and cost of comorbidities in patients with neuromyelitis optica spectrum disorder

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is associated with various comorbidities, including non-autoimmune and autoimmune conditions. The burden and cost of illness for NMOSD are unclear, particularly in the context of comorbidities.

METHODS

Claims data from IBM MarketScan Commercial and Medicare Supplemental Databases between 2014 and 2018 were analyzed. Patients with NMOSD were specified as having inpatient or outpatient claims for NMOSD diagnosis or specific NMOSD symptoms claims and no subsequent claims for multiple sclerosis (MS) or use of MS disease-modifying therapy (DMT). Continuous enrollment ≥ 6 months before and ≥ 1 year after the first claim (index date) was required for study inclusion. Total costs stratified by comorbidities within 12 months post-index date were calculated per patient and compared 1:5 with matched non-NMOSD controls.

RESULTS

A total of 162 patients with NMOSD and 810 non-NMOSD controls were evaluated. A significantly higher proportion of NMOSD patients had comorbidities than non-NMOSD controls (66.7% vs 41.5%; P < 0.001). Concomitant autoimmune disease occurred in 19.1% vs 4.9% (P < 0.001) of patients with NMOSD vs non-NMOSD controls. NMOSD patients incurred significantly higher total median (interquartile range) healthcare costs per patient ($68,386.48 [$23,373.54-$160,862.70]) than matched non-NMOSD controls with autoimmune disease ($17,215.13 [$6715.48-$31,441.93]; P < 0.001) or patients with NMOSD without autoimmune comorbidity ($23,905.42 [$8632.82-$67,251.54]; P = 0.022). Similarly, patients with NMOSD and non-autoimmune comorbidities incurred higher median healthcare costs than matched controls.

CONCLUSIONS

Patients with NMOSD experience significant disease burden and cost that are amplified by comorbidities. Effective therapies are needed, particularly for patients with concomitant autoimmune disease.

Multiple sclerosis-like NMOSD patients suffer severe worsening of status after fingolimod initiation

BACKGROUND

Initial clinical manifestations of NMOSD may rarely overlap with MS. Fingolimod may trigger severe attacks in patients with NMOSD previously misdiagnosed as MS. These cases are rare and their pathophysiology remains elusive.

METHODS

We recruited all NMOSD patients treated by fingolimod in a single-center cohort of Afro-Caribbean neuro-inflammatory patients in Fort-de-France (French West Indies). Six patients were collected from the literature.

RESULTS

Among 622 patients followed locally for MS, 101 received fingolimod and two suffered severe attacks revealing a typical NMOSD presentation. These two patients were found to have AQP4-IgG. The risk of misdiagnosed NMOSD in MS in our high-risk Afro-Caribbean patients was estimated to be 1.9% (0 to 4.7%). Among the whole cohort, relapses occurred within a month after fingolimod initiation in five patients. All attacks were severe and contrasted with previously benign attacks, suggesting a shift to a more severe disorder. An unusual finding in these patients was large brain lesions.

CONCLUSION

AQP4-IgG should be obtained before initiation of fingolimod in high-risk patients, especially in those from areas of high NMOSD prevalence.

Prevalence of neuromyelitis optica spectrum disorder in Belo Horizonte, Southeast Brazil

BACKGROUND

Studies on the prevalence of neuromyelitis optica spectrum disorder (NMOSD) are still scarce. The aim of the current study was to determine the prevalence rate of NMOSD in Belo Horizonte, southeast Brazil, where the prevalence rate of multiple sclerosis (MS) has already been established.

METHODS

For this observational study, eligible patients had to meet the 2015 International Panel for Neuromyelitis Optica Diagnosis, be seen at the study center between January 2000 and February 2019 and live in Belo Horizonte. The prevalence rate of NMOSD was estimated based on the number of MS and NMOSD patients seen at same Center during the same period, and the previously established prevalence of MS in Belo Horizonte.

RESULTS

During the study period, there were 69 patients with NMOSD, 60 (87.0%) of whom were females, and 44 (63.8%) non-whites. The median age at disease onset was 36.7 (4-72) years, the mean EDSS score 4.78±2.36, and the mean ARR 0.57±0.43. Anti-aquaporin-4 immunoglobulin testing was available for 61 (88.4%) patients, of whom 41 (67.2%) had a positive result. During the same period, 280 MS patients were seen. Considering the local known prevalence rate of MS of 18.1/100,000 inhabitants, the estimated NMOSD prevalence rate in Belo Horizonte was 4.52/100,000 (95% CI 3.72-5.43) inhabitants.

CONCLUSION

The prevalence rate of NMOSD in Belo Horizonte is high as compared with those found in most of the studies reported to date.

Satralizumab for the Treatment of Neuromyelitis Optica Spectrum Disorders

OBJECTIVE

To review the pharmacological characteristics, clinical evidence, and place in therapy of satralizumab for the treatment of neuromyelitis optica spectrum disorders (NMOSDs).

DATA SOURCES

A comprehensive literature search was conducted in PubMed (January 2000 to October 15, 2020). Key search terms included satralizumab and neuromyelitis optica spectrum disorders. Other sources were derived from product labeling and ClinicalTrials.gov.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles identified from the data sources were reviewed and evaluated. Phase I, II, and III clinical trials were included.

DATA SYNTHESIS

NMOSD is an autoimmune disease characterized by inflammatory lesions in the optic nerves and spinal cord. Interleukin-6 is involved in the pathogenesis of the disorder. Satralizumab is a humanized monoclonal antibody targeting the interleukin-6 receptor. Phase III trials showed that protocol-defined relapse was 30% for satralizumab and 50% for placebo (P = 0.018) when patients with NMOSD were treated with satralizumab monotherapy; protocol-defined relapse was 20% for satralizumab and 43% for placebo (P = 0.02) when satralizumab was added to immunosuppressant treatment. Satralizumab is generally well tolerated, with common adverse effects including injection-related reaction.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Satralizumab has the potential to become a valuable treatment option for patients with NMOSD.

CONCLUSION

Satralizumab appears to be safe and effective as monotherapy or in combination with an immunosuppressant for patients with NMOSD and has the potential to become a valuable treatment option for these patients.