The prevalence of multiple sclerosis in Belo Horizonte, Brazil

Systematic literature review and meta-analysis of the prevalence of secondary progressive multiple sclerosis in the USA, Europe, Canada, Australia, and Brazil

Background

Secondary progressive multiple sclerosis (SPMS) is a subtype of multiple sclerosis (MS), which is a chronic neurological disease, characterised by inflammation of the central nervous system. Most of MS patients eventually progress to SPMS. This study estimates the prevalence of SPMS in the United States of America, Europe, Canada, Australia, and Brazil.

Methods

A systematic literature search of the Medline and Embase databases was performed using the OVID™ SP platform to identify MS epidemiological studies published in English from database inception to September 22, 2020. Studies reporting the prevalence of MS and proportion of SPMS patients in the included population were selected. The pooled prevalence of SPMS was calculated based on the proportion of SPMS patients. The Loney quality assessment checklist was used for quality grading. A meta-analysis of the proportions was conducted in RStudio.

Results

A total of 4754 articles were retrieved, and prevalence was calculated from 97 relevant studies. Overall, 86 medium- and high-quality studies were included in the meta-analysis. Most studies were conducted in European countries (84 studies). The estimated pooled prevalence of SPMS was 22.42 (99% confidence interval: 18.30, 26.95)/100,000. The prevalence of SPMS was more in the North European countries, highest in Sweden and lowest in Brazil. A decline in SPMS prevalence was observed since the availability of oral disease-modifying therapies. We also observed a regional variation of higher SPMS prevalence in urban areas compared with rural areas.

Conclusion

High variability was observed in the estimated SPMS prevalence, and the quality of the studies conducted. The influence of latitude and other factors known to affect overall MS prevalence did not fully explain the wide range of inter-country and intra-country variability identified in the results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02820-0.

Human endogenous retrovirus and multiple sclerosis: A review and transcriptome findings

Multiple Sclerosis is an autoimmune disease with an unknown etiology. Both genetic and environmental factors are believed to trigger MS autoimmunity. Among the environmental factors, infectious agents have been extensively investigated, and the Human Endogenous Retroviruses (HERVs), especially HERV-W, are believed to be associated with MS pathogenesis. HERVs are derived from ancestral infections and comprise around 8% of the human genome. Although most HERVs are silenced, retroviral genes may be expressed with virion formation. There is extensive evidence of the relationship between HERV-W and MS, including higher levels of HERV-W expression in MS patients, HERV-W protein detection in MS plaques, and the HERV-W env protein inducing an inflammatory response in in vitro and in vivo models. Here we discuss possible links of HERVs and the pathogenesis of MS and present new data regarding the diversity of HERVs expression in samples derived from MS patients.

Prevalence of multiple sclerosis in key cities of Brazil. A study in Joinville, Southern Brazil

BACKGROUND

The Brazilian Committee for Treatment and Research in Multiple Sclerosis (BCTRIMS) has launched an initiative to determine the prevalence of multiple sclerosis (MS) in Brazil, based on key cities deemed representative of their regions in terms of demographic and environmental features.

OBJECTIVE

To investigate the prevalence rate of MS in Joinville.

METHODS

We reviewed the medical records of all patients who lived in Joinville and met the 2010 McDonald's diagnostic criteria revised for MS on the prevalence day (March 11, 2016). Potential MS patients included individuals treated by all practicing neurologists in the city and the ones found in patients' association and the database of the Municipal Department of Health. Advertisements about the survey were also broadcast on radio and television. Patients who were not living in Joinville on the prevalence day were excluded. All potential MS patients were invited to an in-person diagnostic review, carried out by a panel of experienced neurologists with special expertise in MS on March 11, 2016.

RESULTS

The MS prevalence rate was 13.5 per 100,000 inhabitants (95% confidence interval [95%CI] 12.9-14.0/100,000). A total of 51 (66.2%) participants were females, and 26 (33.7%) were males (female to male ratio=1.9:1). Out of the 77 patients, 73 (94.8%) were Caucasians, and four (5.1%) were mixed-race.

CONCLUSIONS

Despite its latitude location and European colonization, the prevalence rate was below expectation. The intense internal migration from regions with lower MS prevalence rates to Joinville may have played a role in attenuating the increased risk of MS associated with latitude gradient and European ancestry. Prevalence studies in other cities from Southern Brazil with no significant internal migration and taking part in this broad project may clarify this issue.

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.

Population-based Study of 24 Autoimmune Diseases Carried Out in a Brazilian Microregion

In Brazil, epidemiological data on autoimmune diseases are scarce due to the lack of a specific policy of attention to this group of diseases. This study aimed to estimate the general and relative prevalence of the diseases presented, as well as to know the sociodemographic profile of the identified cases. This cross-sectional study was conducted with an epidemiological survey of patients with confirmed diagnosis of autoimmune diseases from primary health care in the Aguas Formosas microregion, Minas Gerais, Brazil. We have included all new and old cases found of individuals of both sexes and all ages, including those who died and emigrated during this period. A total of 407 carriers and 24 different autoimmune diseases were identified. The prevalence of autoimmune diseases in this region was 673.6 cases per 100,000 inhabitants [95% confidence interval (CI): 609.8-742.4]. Highest prevalence was identified for Hashimoto's thyroiditis 140.6 cases per 100,000 (95% CI: 112.4-173.9), followed by vitiligo 132.4 cases per 100,000 (95% CI: 105.0-164.8), and rheumatoid arthritis 105.9 cases per 100,000 (95% CI: 81.6-135.3). The sex ratio was higher in females (69%), the most affected age group was over 60 years (30.5%), with greater predominance in the urban area (81.3%). Our data showed the general and relative prevalence of the identified diseases, allowing to know the sociodemographic profile of the identified cases and the epidemiological trend of these morbidities in a low-income Brazilian region.

Prevalence of multiple sclerosis in Goiânia, Goiás, Brazil

OBJECTIVE

Multiple sclerosis (MS) prevalence, in some cities in Brazil, was estimated and was found to range from 0.75 to 30.7/100,000. The reasons for such a large variation in rates of prevalence are not clear, but environment and genetics help to explain this phenomenon.

METHODS

A cross-sectional study using three sources of case ascertainment to estimate the prevalence of MS in the city of Goiânia in December, 2015.

RESULTS

A total of 318 MS patients was found after removing overlapping sources. The prevalence of MS was 22.4/100,000 population.

CONCLUSION

Our study was the first in Goiás and the third in the midwest region, and we found a great increase in the prevalence of MS in the region. It is necessary to perform other studies using the same methodology for a more accurate evaluation of the true prevalence of MS in Brazil.

Multiple sclerosis epidemiology in Latin America: An updated survey

Novel epidemiological data have appeared in recent years in Latin America (LATAM). The objective of this study was to perform an updated systematic review of the epidemiology of the disease reported in LATAM.

Clinical and epidemiological profile of patients diagnosed with multiple sclerosis in João Pessoa, Paraíba, Brazil

Prevalence rates of multiple sclerosis (MS) suggest an interrelationship between genetic and environmental factors, ranging worldwide.Objectives Clinical and epidemiological characterization of MS patients in João Pessoa, Paraíba city.Methods Study involving patients treated in five services in the city.Results It included 87 patients with MS, representing a prevalence of 12.0 cases/100,000 population, mainly women (77%) and white people (66.7%) with mean age of 43 years and average age of the first outbreak of 32.2 years. Motor symptoms (65.5%) and relapsing-remitting clinical form (78.2%) predominated; the average of the Expanded Disability Status Scale (EDSS) scores was 3.5 and 72% used a type of immunomodulatory drug. There was a positive correlation between the number of outbreaks and the duration of the disease with EDSS scores.Conclusions The prevalence of the disease is considered average. The clinical and epidemiological characteristics are in line with most similar Brazilian studies.

The profile of patients followed at the Neuroimmunology Clinic at UNIFESP: 20 years analysis

Objective To describe the clinical activities at the Neuroimmunology Clinic of the Universidade Federal de São Paulo (UNIFESP) from 1994 to 2013. Method The final diagnosis of all patients that attended the center was reviewed and established upon specific guidelines for each disease. The number of total appointments and extra clinical activities (reports and prescriptions) were also analyzed, as are part of routine activities. Results 1,599 patients attended the Clinic from 1994 to 2013: 816 with multiple sclerosis (MS), 172 with clinical isolated syndromes, 178 with neuromyelitis optica (NMO), 216 with other demyelinating disease, 20 with metabolic disorder, 42 with a vascular disease and 155 with other or undetermined diagnosis. A mean 219 outpatient visits and 65 extra clinical activities were performed monthly. Conclusion We identified that 15% of patients seen have NMO. As patients with NMO have a more severe disease than MS, this data may be important for planning local health care policies.

The prevalence of multiple sclerosis in Santa Maria, Rio Grande do Sul, Brazil

Multiple sclerosis (MS) is one of the leading causes of neurologic deficits in young adults and can lead to physical, intellectual and emotional problems. Approved treatments are expensive and are among the 10 highest budgets of the Brazilian Health Ministry. Given the diverse prevalence of MS among Brazilian regions, it is important to determine prevalence rates across the country. Seven studies have assessed MS in Brazil and reported rates ranging from 15 cases to 18 cases per 100,000 inhabitants. It has been hypothesized that this rate is even higher in southern Brazil, which has a high proportion of European heritage (mostly German and Italian) immigrants. Here, we report that the prevalence of MS in the city of Santa Maria, Rio Grande do Sul, Brazil, is 27.2 cases/100,000 inhabitants.

Cost of care according to disease-modifying therapy in Mexicans with relapsing-remitting multiple sclerosis

Limited data exist on the costs of care of patients with multiple sclerosis (MS) in low- to middle-income nations. The purpose of this study was to describe the economic burden associated with care of Mexican patients with relapsing-remitting MS in a representative sample of the largest institution of the Mexican public healthcare system. We analysed individual data of 492 patients (67% women) with relapsing-remitting MS registered from January 2009 to February 2011 at the Mexican Social Security Institute. Direct costs were measured about the use of diagnostic tests, disease-modifying therapies (DMTs), symptoms control, medical consultations, relapses, intensive care and rehabilitation. Four groups were defined according to DMT alternatives: (1) interferon beta (IFNβ)-1a, 6 million units (MU); (2) IFNβ-1a, 12MU; (3) IFNβ-1b, 8MU; and (4) glatiramer acetate. All patients received DMTs for at least 1 year. The most frequently used DMT was glatiramer acetate (45.5%), followed by IFNβ-1a 12MU (22.6%), IFNβ-1b 8MU (20.7%), and IFNβ-1a 6MU (11.2%). The mean cost of a specialised medical consultation was €74.90 (US $107.00). A single relapse had a mean total cost of €2,505.97 (US $3,579.96). No differences were found in annualised relapse rates and costs of relapses according to DMT. However, a significant difference was observed in total annual costs according to treatment groups (glatiramer acetate being the most expensive), mainly due to differences in unitary costs of alternatives. From the public institutional perspective, when equipotent DMTs are used in patients with comparable characteristics, the costs of DMTs largely determine the total expenses associated with care of patients with relapsing-remitting MS in a middle-income country.

Antiparasitic antibodies occur with similar frequency in patients with clinically established multiple sclerosis with or without oligoclonal bands in the cerebrospinal fluid

The "hygiene hypothesis" postulates an inverse relationship between the prevalence of parasitic infections and the frequency of multiple sclerosis (MS). Objective: It was to study whether antibodies against parasites could be demonstrated more frequently in blood serum from MS patients with oligoclonal bands (OCB) than from MS patients without OCB. Methods: We studied serum samples from 164 patients who had previously been analyzed to investigate OCB. Parasitic antibodies were studied through unidimensional electrophoresis of proteins on polyacrylamide gel against Taenia antigens, searching for antiparasitic specific low molecular weight antibodies and also for antiparasitic nonspecific high molecular weight antibodies. Results: Two of the 103 patients with no evidence of OCB had antibodies of low molecular weight and 59 of them had antibodies of high molecular weight. Of the 61 patients with evidence of OCB, one showed antibodies of low molecular weight and 16 showed antibodies of high molecular weight. Conclusion: Antiparasitic antibodies are detected with similar frequency in MS patients with OCB and in MS patients without OCB.