MS and Disability Progression in Latin America, Africa, Asia and the Middle East: A Systematic Review

BACKGROUND

There is evidence of an increased prevalence and disease burden of Multiple Sclerosis (MS) in parts of the world where the risk was once considered low, such as Latin America (LA), Sub-Saharan Africa, Asia and the Middle East-North Africa (MENA). Despite the growing number of clinical reports, the phenotype and course of MS in these regions remains understudied compared with Europe and North America. We aimed to investigate MS phenotypes and long-term clinical outcomes across these regions.

METHOD

A Boolean search of the medical literature was conducted between January 1980 and April 30, 2020. PubMed, SCOPUS, Global Health, and the Cochrane databases, were used to identify all relevant citations. Articles were collated and managed on Covidence® software. We independently appraised the articles for meeting study criteria and for quality using the Critical Appraisal Skills Program (CASP) and the Specialist Unit for Review Evidence (SURE) system.

RESULTS

A total of 1,639 studies were imported for screening. After removing 545 duplicates, two authors assessed 1,094 abstracts and selected 515 for full-text screening. 72 articles met study criteria, including 19 studies from LA, 4 from sub-Saharan Africa, 24 from Asia and 25 from MENA. The overall sex ratio was 2.5:1 (female: male). Disability was assessed using the Expanded Disability Status Scale (EDSS). Longitudinal disability progression and time to standard endpoints was compared by region and with relevant Western reports. Patients with MS living in the MENA region appear to reach disability milestones faster than those in the Western world, although this finding is not uniform. South Asia shows distinct disability features compared with East Asia, more closely resembling those of the West. Disease morbidity in East Asia appears more benign than in the West after careful exclusion of neuromyelitis optica spectrum disorder cases. Populations in LA tend to have similar MS features to the Western world, but some exceptions exist, including African descendants that reach disability milestones earlier. Using all studies with appropriate survival analysis, the mean time to EDSS 6.0 was 16.97 years with a heterogeneity index of 24.59.

CONCLUSION

The clinical phenotypes and disability progression of MS in LA, Africa, Asia and the MENA region have similarities to Western MS. In some regions and subpopulations there is evidence of a more aggressive course, possibly due to a combination of genetic and environmental factors. More population-based longitudinal data are needed, particularly in Sub-Saharan Africa.

Epidemiological findings of neuromyelitis optica spectrum disorders in a Venezuelan study

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD), is a rare autoimmune inflammatory disease of the central nervous system. Since the countries of Latin America (LATAM) show contrast in geographic, social, environmental factors, and genetic heterogeneity, the information about NMOSD epidemiology in the region allows a better understanding of the disease and its clinical outcome.

OBJECTIVES

To determine the prevalence, relative frequency (RF), and clinical characteristics of NMOSD in a multiethnic Venezuelan cohort of patients with demyelinating disorders.

METHODS

We conducted a retrospective descriptive multicenter study of hospital case records of individuals with an established diagnosis of MS and NMOSD in the National Program for Multiple sclerosis (MS) from 2011 to 2018. We selected those NMOSD cases based on the 2006 Wingerchuck and the 2015 International panel for the diagnosis of Neuromyelitis optica (IPND) criteria.

RESULTS

We identified 249 patients with NMOSD. The prevalence was 2.11 per100,000 individuals (95% confidence interval (CI)1.85 2.37), the RF was 23%, and the MS/NMOSD ratio was 3.2:1. The average disease onset occurred by the fourth decade of life (34±14.8 years of age); with a strong female predominance (female to male ratio: 4:1). Mestizos constituted 86,7% of this cohort. Most of the patients presented initially with simultaneous optic neuritis (ON) and acute transverse myelitis (ATM) and a recurrent course was registered in 82.3% of cases. The mean of the expanded disability status scale (EDSS) was 3.5 (IQR 2-7). Abnormal brain and spine MRI were present in 47.8% and 81.1% of patients, respectively. Antibodies against aquaporin-4 (AQP4) which were measured through a cell-based assay were positive in 55.3% of the individuals tested. The most used immunosuppressant agent was Azathioprine (57.4%).

CONCLUSION

NMOSD in Venezuela affects mainly young Mestizo women and shows one of the highest relative frequency in the region. Planning and developing healthcare programs for underserved populations as well as more comprehensive LATAM studies are required to identify the distribution and variations of its epidemiological picture.

Clinical and radiological profile of neuromyelitis optica spectrum disorders in an Ecuadorian cohort

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a complex disease characterized by a severe inflammation of the central nervous system (CNS). This disease typically manifests with recurrent optic neuritis (ON) and acute transverse myelitis (ATM). The clinical and radiological spectrum of NMOSD is little known in Latin America (LATAM) and few reports have been published in the literature so far. In Ecuador, no reports on NMOSD have been published. For this reason we aimed to assess the demographic, clinical and imaging characteristics of patients with NMOSD from third level hospitals from Ecuador.

METHODS

This is a descriptive study in which we assessed medical reports of patients with inflammatory demyelinating diseases who were attended in third level hospitals from Ecuador in 2017. Then we applied the 2015 diagnostic criteria, those patients who met the new NMOSD diagnostic criteria were selected and analyzed. Additionally, exploratory sub-analyses were subsequently carried out.

RESULTS

We identified 59 patients with NMOSD, the relative frequency of NMOSD was 15.9%. The multiple sclerosis (MS) /NMOSD ratio was 5.2:1. Twenty four percent of patients were newly defined as having NMOSD when 2015 criteria was applied. The median time to diagnoses was shorter by the 2015 criteria than 2006 criteria (p<0.001). NMOSD was more prevalent in women (female/male ratio 4.4:1). The disease onset was more frequent at the fourth decade of life. The most common symptoms at the disease onset were ON and the association of ON with ATM. The mean of expanded disability status scale (EDSS) was 4.8 (SD±1.8). Concomitant autoimmune diseases were infrequent in this population (11.9%). The brain magnetic resonance imaging (MRI) abnormalities were present in 25.7% of patients at disease onset. Spinal cord MRI showed longitudinally extensive transverse myelitis (LETM) in 91.5% of cases. Recurrent NMOSD was frequent in this cohort (88%). Positivity for antibodies against aquaporin-4 (AQP4-IgG) which was measured through indirect immunofluorescence assay (IIF) was identified in 81% of the patients tested. Patients with seronegative AQP4-IgG had higher grade of disability than seropositive patients (p<0.05). Ninety eight percent of patients received treatment with immunosuppressive drugs. Three patients died due to gastric cancer (1 patient) and infectious diseases (2 patients).

CONCLUSIONS

This is the first descriptive study in an Ecuadorian cohort of patients with NMOSD. We show a wide epidemiological, clinical and radiological spectrum of NMOSD.

Is Asian type MS an MS phenotype, an NMO spectrum disorder, or a MOG-IgG related disease?

BACKGROUND

A specific particularity of neurological diseases in Asia is the relative commonality of neuromyelitis optica (NMO) and Asian type MS (OSMS). Both conditions also occur in South American patients. The Brazilian population differs from the European and the Asian populations due to the mixture of ancestralities between European colonizers and African slaves. To better know the clinical characteristics of Brazilian patients with Asian type MS this study aimed to analyze the clinical, radiological and serological data that would help to distinguish between OSMS and NMO and clarify, in a Non-Asian population, if OSMS is an MS phenotype, an NMO spectrum disorder by 2015 classification, or a complement activating antibody to myelin oligodendrocyte glycoprotein (MOG-IgG) antibody-related disease.

METHODS

We selected cases retrospectively with NMO and OSMS in the medical registry of patients with idiopathic inflammatory demyelinating diseases under follow-up since 1997 in Federal Hospital da Lagoa, the principal reference center for MS treatment in Rio de Janeiro, Brazil. OSMS has selective involvement of the optic nerve and spinal cord with no cerebral or cerebellar symptoms associated with small spinal cord lesions and negativity for the aquaporin-4 antibody (AQP4-IgG). NMO full-filled the revised criteria (2006) associated with longitudinally extensive transverse myelitis (LETM). We recorded the following data: ethnicity/skin color, neurologic impairment "at nadir" and "at recovery" of the index events (optic neuritis and transverse myelitis), long term disability, mortality, health quality of life scores by the SF-36 questionnaire, CSF IgG oligoclonal bands and serological AQP4-IgG and MOG-IgG antibodies tested by Cell-based assay. The last brain MRIs were classified as either satisfying or not satisfying MAGNIMS radiologic criteria for MS or typical or not typical for NMOSD. The new classification of NMO spectrum disorders (2015) was applied.

RESULTS

Forty-one OSMS and 122 NMO cases were analyzed. OSMS affected mainly young white women, causing unilateral optic neuritis and partial myelitis with excellent recovery. After a mean disease duration of 20 years, 90% of the patients had free ambulation, and 70% had a mild disability or no disability. Only 7.2% presented a secondary progressive course, and no deaths occurred. All cases had negativity to AQP4-IgG and MOG-IgG biomarkers. 95% had resonance criteria for MS. OSMS differed from NMO by ethnicity, morbidity, and mortality: most were African descendants, with severe motor and visual dysfunction, and one third died. Only NMO cases full-filled the new NMOSD classification (52 AQP4-IgG positive, 29 AQP4-IgG negative, and 41 AQP4-IgG unknown).

CONCLUSION

In Brazilian patients, OSMS and NMO are different immune-mediated diseases. OSMS is a milder MS phenotype.

Treating neuromyelitis optica with azathioprine: 20-year clinical practice

BACKGROUND

Neuromyelitis optica leads to severe disability. Preventive treatment includes steroids and immunosuppressants, and indications are based on retrospective and observational studies.

METHODS

We analyzed 158 patients with neuromyelitis optica regarding disease course, prognostic factors, and treatment response to azathioprine, a widely available low-cost drug. Disability accumulation was used as an endpoint to treatment response.

RESULTS

Eight patients with monophasic and 150 with relapsing disease with a median 7 years of disease duration and 4.6 years of follow-up were evaluated. All relapsing patients received preventive treatment, 100 with azathioprine. Only 30% reached Expanded Disability Status Scale (EDSS) 6, and 69% of patients presented no disability accumulation along follow-up. The time under azathioprine and prednisone use were inversely correlated to the hazard of disability accumulation (hazard ratio (HR) = 0.981 and 0.986, respectively; p < 0.01). Each month under azathioprine use reduced disability accumulation by 2.6% (HR = 0.974, p < 0.01), corresponding to an 80% decrease in EDSS progression over 5 years.

INTERPRETATION

We report less disability accumulation than previous series on patients with neuromyelitis optica, two-thirds presenting no disability accumulation along follow-up. Continued azathioprine used from early disease onset was strongly associated to maintenance of neurological function and should be offered as a viable option for low-income scenarios.

Central nervous system neuroinflammatory disorders in Asian/Pacific regions

PURPOSE OF REVIEW

The discovery of aquaporin-4 (AQP4) antibodies with high specificity for neuromyelitis optica spectrum disorder (NMOSD) has induced tremendous changes in the approach and management of central nervous system (CNS) neuroinflammatory disorders. Owing to the increasing availability of the AQP4 antibody assay and evolution of diagnostic criteria for multiple sclerosis and NMOSD, recent studies have reevaluated CNS neuroinflammatory disorders. This review describes recent advances in the understanding of CNS neuroinflammatory disorders in Asian/Pacific regions.

RECENT FINDINGS

Although multiple sclerosis prevalence is lower in Asian countries than in Western countries, the overall clinical features of multiple sclerosis are comparable between these countries. Hospital-based studies have reported that the frequency of NMOSD is higher in Asian populations (22-42%) than in white populations (2-26%). Despite improvements in the AQP4 antibody assay, AQP4 antibodies are not detected in certain patients with NMOSD. Recently, myelin oligodendrocyte glycoprotein (MOG) antibodies have been identified in AQP4 antibody-negative patients with the NMOSD phenotype, and the clinical features differ slightly between MOG antibody-positive patients and AQP4 antibody-positive patients.

SUMMARY

The understanding of CNS neuroinflammatory disorders in Asian/Pacific regions continues to evolve owing to the discovery of new biological markers and recognition of broader clinical phenotypes.

Differential diagnosis of multiple sclerosis in Latin America

Improvement of multiple sclerosis (MS) diagnoses leads to earlier and correct disease management. The differential diagnostic workup for MS comprises a large variety of medical conditions. There are general guidelines and criteria for diagnosing MS worldwide, but awareness of regional differences needs to be kept in mind. Latin American patients who are screened for MS diagnoses may require an approach that is not exactly the same as that used for patients in North America, western Europe or Asia. In the present review, the conditions that are important for the differential diagnoses of MS in Latin America are reviewed. They include infections, metabolic diseases, nutritional deficits and other autoimmune conditions that physicians in charge of these patients need to be familiar with.

Epidemiology of neuromyelitis optica in Latin America

A major development over the past two decades was the recognition of recurrent neuromyelitis optica (NMO) as a particular central nervous system disorder different from multiple sclerosis (MS). Here we reviewed the epidemiology of NMO in Latin America (LATAM). A predominance of a mixed population is found in this region. Recurrent NMO in black women was described in the Caribbean Islands and in Rio de Janeiro. The prevalence of NMO in LATAM varied from 0.37/100,000 (Volta Redonda city) to 4.2/100,000 inhabitants (Caribbean Islands). NMO differs significantly from MS with respect to gender, ethnicity, morbidity and genetic susceptibility. An association of the HLA DRB1*03 alleles with NMO was described in the French Antilles, Ribeirão Preto, Rio de Janeiro and Mexico. It is not common to find familial forms of NMO. NMO represents 11.8% of all inflammatory idiopathic diseases in South America (SA). In SA, the highest frequency of NMO occurs in African Brazilian young women. The overall relative frequency of NMO among MS cases in this region was 14%, decreasing following a north-south gradient, which parallels the percentage of nonwhite people.

Disability and progression in Afro-descendant patients with multiple sclerosis

ABSTRACT Multiple sclerosis (MS) prevalence is higher in Caucasian (CA) populations, narrowing the analysis of the impact of Afro-descendant (AD) populations in disease outcomes. Even so, recent studies observed that AD patients have a more severe course. The main objective of this study is to confirm and discuss, through a systematic review, that being AD is a risk factor for disability accumulation and/or severe progression in patients with MS. A systematic review of published data in the last eleven years was performed, which evaluated clinical aspects and long term disability in patients with MS. Fourteen studies were included. Of these fourteen articles, thirteen observed a relationship between ancestry and poorer outcome of MS. African ancestry is a condition inherent in the patient and should be considered as an initial clinical characteristic affecting prognosis, and influencing which therapeutic decision to make in initial phases.

Central Nervous System Idiopathic Inflammatory Demyelinating Disorders in South Americans: A Descriptive, Multicenter, Cross-Sectional Study

The idiopathic inflammatory demyelinating disease (IIDD) spectrum has been investigated among different populations, and the results have indicated a low relative frequency of neuromyelitis optica (NMO) among multiple sclerosis (MS) cases in whites (1.2%-1.5%), increasing in Mestizos (8%) and Africans (15.4%-27.5%) living in areas of low MS prevalence. South America (SA) was colonized by Europeans from the Iberian Peninsula, and their miscegenation with natives and Africans slaves resulted in significant racial mixing. The current study analyzed the IIDD spectrum in SA after accounting for the ethnic heterogeneity of its population. A cross-sectional multicenter study was performed. Only individuals followed in 2011 with a confirmed diagnosis of IIDD using new diagnostic criteria were considered eligible. Patients’ demographic, clinical and laboratory data were collected. In all, 1,917 individuals from 22 MS centers were included (73.7% female, 63.0% white, 28.0% African, 7.0% Mestizo, and 0.2% Asian). The main disease categories and their associated frequencies were MS (76.9%), NMO (11.8%), other NMO syndromes (6.5%), CIS (3.5%), ADEM (1.0%), and acute encephalopathy (0.4%). Females predominated in all main categories. The white ethnicity also predominated, except in NMO. Except in ADEM, the disease onset occurred between 20 and 39 years old, early onset in 8.2% of all cases, and late onset occurred in 8.9%. The long-term morbidity after a mean disease time of 9.28±7.7 years was characterized by mild disability in all categories except in NMO, which was scored as moderate. Disease time among those with MS was positively correlated with the expanded disability status scale (EDSS) score (r=0.374; p=<0.001). This correlation was not observed in people with NMO or those with other NMO spectrum disorders (NMOSDs). Among patients with NMO, 83.2% showed a relapsing-remitting course, and 16.8% showed a monophasic course. The NMO-IgG antibody tested using indirect immunofluorescence (IIF) with a composite substrate of mouse tissues in 200 NMOSD cases was positive in people with NMO (95/162; 58.6%), longitudinally extensive transverse myelitis (10/30; 33.3%) and bilateral or recurrent optic neuritis (8/8; 100%). No association of NMO-IgG antibody positivity was found with gender, age at onset, ethnicity, early or late onset forms, disease course, or long-term severe disability. The relative frequency of NMO among relapsing-remitting MS (RRMS) + NMO cases in SA was 14.0%. Despite the high degree of miscegenation found in SA, MS affects three quarters of all patients with IIDD, mainly white young women who share similar clinical characteristics to those in Western populations in the northern hemisphere, with the exception of ethnicity; approximately one-third of all cases occur among non-white individuals. At the last assessment, the majority of RRMS patients showed mild disability, and the risk for secondary progression was significantly superior among those of African ethnicity. NMO comprises 11.8% of all IIDD cases in SA, affecting mostly young African-Brazilian women, evolving with a recurrent course and causing moderate or severe disability in both ethnic groups. The South-North gradient with increasing NMO and non-white individuals from Argentina, Paraguay, Brazil and Venezuela confirmed previous studies showing a higher frequency of NMO among non-white populations.

Clinical manifestations of neuromyelitis optica in male and female patients

Neuromyelitis optica (NMO) is a severe, idiopathic, immuno-mediated, inflammatory demyelinating disease of the central nervous system. We examined the clinical features between male and female NMO patients, for which not much data exist. One hundred and eight Chinese Han patients with NMO were analysed retrospectively, all had been detected for the aquaporin-4 (AQP4) antibody using a cell-based assay. Of 108 NMO patients, 92 were female and 16 were male (female/male = 5.75). Ninety-four (87%) were positive for the AQP4 antibody in their serum and/or cerebral spinal fluid. Aquaporin-4 antibody-positive NMO patients had a higher female/male ratio than the negative group (P = 0.001). Female NMO patients had a higher positive rate of the AQP4 antibody than male NMO patients (92.4 vs 56.3%, P = 0.001). All NMO male patients were divided according to their AQP4 antibody status. 77.8% (7/9) of patients in the seropositive group had initial optic neuritis, while only one patient (14.3%, 1/7) in the negative group had optic neuritis (P = 0.041). Limb paraesthesia was reported in only one patient in the negative group (11.1%), but it was reported in all patients in the positive group (100%) (P = 0.001). The mean length of vertebral segments of the spinal cord lesions was 3.6 ± 1.3 in the positive group, while it was 6.6 ± 2.6 in the negative group (P < 0.0001). The involvement of the cervical spinal cord was found in 88.9% (8/9) of the positive members, but only 11.1% in the negative group (P = 0.009). However, the involvement of the thoracic spinal cord was found in 22.2% of patients in the positive group and 85.7% of patients in the negative members (P = 0.041). In conclusion, male NMO is rare and has a low positive rate of AQP4 antibody.

Familial forms of multiple sclerosis and neuromyelitis optica at an MS center in Rio de Janeiro State, Brazil

OBJECTIVE

To describe familial forms of demyelinating diseases from an MS referral center in Río de Janeiro State, Brazil.

METHODS

A descriptive, cross-sectional study was done to identify familial IIDD cases in Hospital da Lagoa, a public hospital where 75% of patients with IIDD who live in Rio de Janeiro state, located in the Southeast region of Brazil, are referred. The diagnoses of all consecutive patients followed in 2011 were reviewed to apply new diagnostic criteria (Wingerchuk et al., 2008). The diagnosis of IIDD was confirmed based on clinical history, neurological examination, MRI of the skull and spinal cord, CSF analysis and investigation of IgG NMO antibodies. The cases that had at least one other relative with IIDD were selected for the study.

RESULTS

Familial forms were found only in the multiple sclerosis (MS) and neuromyelitis optica syndrome (NMOSD) categories. 23 MS families were identified, 60.86% with first degree kinship. It has a Caucasian preponderance, 90% of whom were white. The frequency of early onset was 15% and 20% of the MSf cases have progressive primary course.

CONCLUSION

The frequency of familial cases of IIDD was 6.12% among MS patients and 2.8% in NMO spectrum syndromes.

Biomarkers for neuromyelitis optica

Neuromyelitis optica (NMO) is an acquired, heterogeneous inflammatory disorder, which is characterized by recurrent optic neuritis and longitudinally extensive spinal cord lesions. The discovery of the serum autoantibody marker, anti-aquaporin 4 (anti-AQP4) antibody, revolutionizes our understanding of pathogenesis of NMO. In addition to anti-AQP4 antibody, other biomarkers for NMO are also reported. These candidate biomarkers are particularly involved in T helper (Th)17 and astrocytic damages, which play a critical role in the development of NMO lesions. Among them, IL-6 in the peripheral blood is associated with anti-AQP4 antibody production. Glial fibrillary acidic protein (GFAP) in CSF demonstrates good correlations with clinical severity of NMO relapses. Detecting these useful biomarkers may be useful in the diagnosis and evaluation of disease activity of NMO. Development of compounds targeting these biomarkers may provide novel therapeutic strategies for NMO. This article will review the related biomarker studies in NMO and discuss the potential therapeutics targeting these biomarkers.

Characterization of the spectrum of Korean inflammatory demyelinating diseases according to the diagnostic criteria and AQP4-Ab status

Background

The relative frequencies of demyelinating diseases among Korean patients with idiopathic inflammatory demyelinating disease of the central nervous system (IIDD) have not been sufficiently studied. We therefore describe a cohort of 203 patients with IIDD from three centers in Korea whose syndromes were identified precisely according to international clinical criteria and autoantibody to aquaporin 4 (AQP4-Ab) status.

Methods

In total, 260 consecutive patients were screened and 203 were included from three hospitals in Korea. All were tested for AQP4-Ab by using a cell-based assay. Patients who met the criteria for definite neuromyelitis optica (NMO) or had a positive AQP4-Ab test result were defined as the NMO group. Among the others, patients were assessed if they had acute disseminated encephalomyelitis, multiple sclerosis (MS), acute transverse myelitis, optic neuritis, or other demyelinating disease as a clinically isolated syndrome of the brain.

Results

Eighteen percent of patients were classified as the NMO group, 2% as acute disseminated encephalomyelitis, 18% as MS, 41% as acute transverse myelitis, 11% as optic neuritis, and 8% as other clinically isolated syndrome of the brain. AQP4-Ab was positive in 18% of patients and the relative frequency of NMO to MS (NMO/MS ratio) was 1.06. The mean duration of follow up in our patients was 64 months.

Conclusions

Among Korean patients with idiopathic inflammatory demyelinating diseases, the incidence of NMO may be similar to that of MS, and the overall positivity of AQP4-Ab could be lower than previously reported. In addition, acute transverse myelitis that is not associated with MS or NMO can be relatively common in these patients. Further population-based studies with AQP4-Ab are needed to determine the exact incidence of NMO and other idiopathic inflammatory demyelinating diseases in Korea.