Towards establishing MS prevalence in Latin America and the Caribbean

Prevalence of Multiple Sclerosis in Rosario, Argentina

BACKGROUND

The prevalence and incidence of Multiple Sclerosis have been increasing worldwide over the last decades. Most of the publications during the last years outstand the prevalence in Europe, North America and Latin America. In Argentina, data published on this topic is scarce and most of the studies took place in Buenos Aires. In a recent publication, we reported an MS prevalence rate of 30.3/100,000 in the overall extension of Santa Fe, Argentina, and in that study, we noticed that MS seemed to be more frequent in the southern region of the province.

OBJECTIVE

In this study we aimed to estimate the prevalence of MS in Rosario (the third most populated district of Argentina), placed in the southeastern part of Santa Fe province.

METHODS

This is a population based, cross-sectional study. We studied the members of the Province´s medical Care Program, a health maintenance organization of the public-sector employees that offers medical and health services to 567,819 members in the province 163,513 of whom have permanent residence in Rosario department, being a large representative sample. The selected prevalence date was 30 June 2019. Cases of MS were detected with a thorough search in the electronic databases of affiliates, linking and aggregating datasets.

RESULTS

Seventy-nine MS cases were detected. The mean age was 47.7 (SD 13.5); female to male ratio was 3 to 1; the most frequent phenotype was relapsing-remitting (82.3%) followed by secondary-progressive (15.2%) and primary-progressive (2.5%). The crude prevalence rate of MS in Rosario as on 30 June 2019 was 48.3/100,000 inhabitants (95% CI: 48.28 - 48.35), 63.7/100,000 for females and 28.3/100,000 for males. The age-standardised MS prevalence rate was 43.4/100,000 inhabitants (95% CI:43.37 - 43.43) while the sex-standardised prevalence was estimated at 46.7/100,000 inhabitants (95% CI: 46.68 - 46.74). Making a proportional and linear projection to the total number of inhabitants, we deemed a total of 578 MS cases in Rosario, according to the 2010 census, and projected 620 cases by July 2019.

CONCLUSION

This is the first study that provides epidemiological data of MS prevalence for Rosario. It confirms that there are differences in the distribution of MS in Santa Fe that favour the aggregation of cases in the southern part of the province. It also supplies updated and relevant data on the distribution of MS in Argentina and Latin America.

Prevalence of multiple sclerosis in Cuenca, Ecuador

Background

Methods

Results

Conclusions

Vitamin D and disability in relapsing-remitting multiple sclerosis in patients with a Mexican background

Previous studies of multiple sclerosis (MS) patients have reported an inverse correlation between disability, the number of relapses and vitamin D levels in mostly white patients. It is unclear if this relationship has the same behavior in individuals with Hispanic backgrounds. To determine the relationship between vitamin D serum levels and disability in a sample of Hispanics of a Mexican background with relapsing-remitting multiple sclerosis (RRMS). A cross-sectional study was conducted on 50 RRMS individuals of Mexican background. The Expanded Disability Status Scale (EDSS) score, progression index (PI) and annual relapse rate (ARR) were recorded for each patient. Vitamin D levels were assessed during the summer. Pearson's test was used to evaluate the relationship between vitamin D and EDSS, PI, ARR, and duration of disease evolution. Most patients were females (n = 29, 58%). The mean vitamin D level was 22.3 (± 6.4) ng/ml; the mean EDSS score was 2.2 (± 0.7), ARR 1.3 (± 0.5) and PI1.08 (± 0.6). No correlation was found between vitamin D levels and EDSS scores, ARR, PI or duration of disease. Moderate negative association between vitamin D levels and EDSS was found just in females (<0.0001). No correlation between vitamin D levels and disability was found in this sample of RRMS Mexicans. Longitudinal studies are needed to better understand the impact of Vitamin D in disability and multiple time points.

Absence of the tag polymorphism for the risk haplotype HLA-DR2 for multiple sclerosis in Wixárika subjects from Mexico

The HLA-DRB1*15:01 allele has a demonstrated risk for the development of multiple sclerosis (MS) in most populations around the world. The single nucleotide polymorphism (SNP) rs3129934 is found in linkage disequilibrium with the risk haplotype formed by the HLA-DRB1*15:01 and HLA-DQB1*06:02 alleles, and it is considered a reliable marker of the presence of this haplotype. Native Americans have a null or low prevalence of MS. In this study, we sought to identify the frequency of rs3129934 in the Wixárika ethnic group as well as in Mestizo (mixed race) patients with MS and in controls from western Mexico. Through real-time polymerase chain reaction (PCR) using TaqMan probes, we analyzed the allele and genotype frequencies of rs3129934 in Mestizo individuals with and without MS and in 73 Wixárika subjects from the state of Jalisco, Mexico. The Wixárika subjects were homozygote for the C allele of rs3129934. The allele and genotype frequency in Mestizos with MS was similar to that of other MS populations with Caucasian ancestry. The absence of the T risk allele rs3129934 (associated with the haplotype HLA-DRB1*15:01, HLA-DQ1*06:02) in this sample of Wixárika subjects is consistent with the unreported MS in this Amerindian group, related to absence of such paramount genetic risk factor.

Increasing Incidence and Prevalence of Multiple Sclerosis in Puerto Rico (2013-2016)

BACKGROUND

The incidence of multiple sclerosis (MS) has been increasing worldwide over the past decades. However, this upward trend has not been examined at the country level in Latin America and the Caribbean (LAC). The aims of this study are to examine trends of MS incidence over 4 years and to provide age- and gender-standardized incidence rate estimates for a Caribbean island.

METHODS

Data from the Puerto Rico (PR) MS Foundation's registry was used to identify all newly diagnosed MS cases between 2013 and 2016. MS patients were 18 years and older and met the 2010 revised McDonald criteria. Age- and gender-standardized incidence rates were estimated.

RESULTS

A total of 583 new MS cases were diagnosed in PR from 2013 to 2016. The age- and gender-standardized MS incidence rate for PR increased from 6.1/100,000 in 2013 to 6.7/100,000 in 2016. The annual age-standardized MS incidence rates for females rose from 8.4/100,000 in 2013 to 9.8/100,000 in 2016 and were higher than males, which remained around 3.7/100,000.

CONCLUSION

Incidence estimates for PR were higher than other LAC countries but consistent with MS increases in other world regions. Our findings tend to rule out several prior potential environmental explanations for high MS incidence rates.

Application of the McDonald criteria in Latin America

The diagnosis of multiple sclerosis (MS) is based on neurological symptoms and signs, alongside evidence of dissemination of central nervous system (CNS) lesions in space and time. In the absence of a sensitive and specific diagnostic test, diagnostic criteria are needed for diagnosing MS. The caveat to the application of the McDonald criteria is that alternative diagnoses must be excluded. The prevalence, clinical phenotype and the differential diagnosis of MS may have variations in different populations, especially in Latin America (LATAM). Considering that MS diagnostic criteria were developed with data gathered largely from adult Caucasian European and North American populations, their applicability and accuracy in ethnical/genetic diverse populations may be affected. There are scarce data in our region about the reliability of MS criteria.

Prevalence of multiple sclerosis in Latin America and its relationship with European migration

Multiple sclerosis (MS) is a chronic, degenerative autoimmune inflammatory disease of the central nervous system. The prevalence is different in every continent, changing according to geographical and environmental characteristics. The areas with the highest prevalence in the world are Europe and North America. In Latin America, the prevalence is higher in areas where there was greater European migration, as in the case of Argentina, Chile, Brazil, Uruguay and Mexico, and there have been no identified cases amongst native Indian populations. It should be considered that environmental factors may influence the prevalence of MS in Latin America, and it seems as if there are protective factors such as exposure to ultraviolet radiation and the presence of parasitosis.

Environmental factors influencing multiple sclerosis in Latin America

It is generally accepted that autoimmune diseases like multiple sclerosis (MS) arise from complex interactions between genetic susceptibility and environmental factors. Genetic variants confer predisposition to develop MS, but cannot be therapeutically modified. On the other hand, several studies have shown that different lifestyle and environmental factors influence disease development, as well as activity levels and progression. Unlike genetic risk factors, these can be modified, with potential for prevention, particularly in high-risk populations. Most studies identifying particular lifestyle and environmental factors have been carried out in Caucasian patients with MS. Little or no data is available on the behavior of these factors in Latin American populations. Ethnic and geographic differences between Latin America and other world regions suggest potential regional variations in MS, at least with respect to some of these factors. Furthermore, particular environmental characteristics observed more frequently in Latin America could explain regional differences in MS prevalence. Site-specific studies exploring influences of local environmental factors are warranted.

Incidence of Multiple Sclerosis in Puerto Rico, 2014: A Population-Based Study

BACKGROUND

Multiple sclerosis (MS) affects millions of people worldwide. The estimates for MS incidence are difficult to obtain but are important for understanding MS etiology, developing prevention strategies, and service planning. This study is aimed at estimating the 2014 incidence of MS in Puerto Rico (PR).

METHODS

The PR MS Foundation's registry was used as the data source. Neurologists, specialty pharmacies, MRI centers, health insurance companies, and the PR Department of Health identified MS cases missed by the registry. MS patients were 18 years and older and met the 2010 revised McDonald criteria. Age-standardized MS incidence rates and their corresponding 95% CIs were computed.

RESULTS

A total of 144 new MS cases were diagnosed in 2014. The age-standardized MS incidence rate was 5.1/100,000 (95% CI 4.3-5.9). The incidence rate was 7.1/100,000 (95% CI 5.7-8.5) for females and 2.9/100,000 (95% CI 2.0-3.8) for males. MS cases were mostly females (72.9%) with a mean age of 41.0 years (±1.0).

CONCLUSION

According to the country estimates, PR has a higher MS incidence than other Caribbean and Latin American countries, but a lower incidence compared to countries at higher latitudes. Our findings provide insights into the MS etiology in the Hispanic population that require additional research.

Orofacial evaluation in patients with multiple sclerosis using Nordic Orofacial Test-Screening

OBJECTIVES

The aim of this study is to investigate whether patients with multiple sclerosis (MS) have more orofacial dysfunctions than the general population, using the Nordic Orofacial Test-Screening (NOT-S).

MATERIALS AND METHODS

The NOT-S instrument was applied in 34 patients with MS, who went to the MS Reference Center, Universidade Metropolitana de Santos and 34 healthy patients, matched for gender and age. NOT-S results were compared between patients with MS and control subjects. Disability and disease duration were assessed among the patients, in order to establish whether these parameters might affect the results from NOT-S.

RESULTS

There was no significant difference in orofacial function between patients with MS and control subjects. There was no statistically significant correlation between disability and NOT-S or between disease duration and NOT-S. However, the correlation between disease duration and the degree of disability was statistically significant, thus suggesting that the results are in accordance with what would be expected regarding MS.

CONCLUSIONS

These results indicate that there was no correlation between orofacial dysfunction and MS, although there were some differences in the affected domains.

CLINICAL RELEVANCE

This study points out the orofacial dysfunctions which health professionals should be aware in this population.

Do We Need Worms to Promote Immune Health?

Many immune-mediated diseases like inflammatory bowel disease, multiple sclerosis, type 1 diabetes, asthma, and food allergy appeared to have increased in frequency in developed countries in the latter part of the twentieth century. Reports from less developed countries suggest that the "epidemic" of immune-mediated diseases now is spreading into these regions as well. The "hygiene hypothesis" was developed to partly explain this phenomenon. It has been proposed that modern-day sanitary living has altered our exposure to organisms that provided protection from these diseases in the past. Alternations in the composition of our intestinal flora and fauna could play a role. Helminths are a group of worm-like parasitic organisms that have adapted to live in various regions of their hosts. Epidemiological and some clinical data suggest that these organisms can protect people from developing immune-mediated diseases. Animal experimentation has shown that helminths stimulate the production of regulatory cytokines, activate regulatory T cells, and induce regulatory dendritic cells and macrophages. This could be the mechanism by which they protect the host from these diseases. Early clinical studies also suggest that helminths may prove useful for treating immunological diseases. More sophisticated clinical studies are underway, testing live helminth agents as therapeutic agents. Also, a strong effort is ongoing to discover the agents produced by helminths that modulate host immune responses with an eye on developing new, highly effective immune modulatory therapeutic agent.

Cost analysis of multiple sclerosis in Brazil: a cross-sectional multicenter study

Background

Multiple sclerosis (MS) is a central nervous system disease associated with irreversible progression of disability, which imposes a substantial socioeconomic onus. The objective of this study was to determine the economic impact of multiple sclerosis from the Brazilian household and healthcare system perspectives. Secondary objectives were to assess the impact of fatigue on daily living and health-related quality of life (HRQL) of MS patients.

Methods

This is a cross-sectional study in which Brazilian eligible patients attending eight major MS specialized sites answered an interview capturing data on demographics, disease characteristics and severity, comorbidities, resource utilization, fatigue, utilities and health-related quality of life from November/2011 to May/2012 . Costs were assessed considering a prevalence-based approach within 1 year of resource consumption and were estimated by multiplying the amount used by the corresponding unit cost. Patients were classified as having mild, moderate or severe disability according to the Expanded Disability Status Scale (EDSS).

Results

In total, 210 patients who met eligibility criteria were included, 40 % had mild, 43 % moderate and 16 % severe disability; disability level was missing for 1 %. The average total direct cost per year was USD 19,012.32 (SD = 10,465.96), and no statistically significant differences were not observed according to MS disability level (p = 0.398). The use of disease modifying therapies (DMTs) corresponded to the majority of direct expenditures, especially among those patients with lower levels of disability, representing around 90 % of total costs for mild and moderate MS patients. It was also observed that expenses with medical (except DMTs) and non-medical resources are higher among patients with more severe disease. Worsening disability also had an important influence on health-related quality of life and self-perceived impact of fatigue on daily living.

Conclusion

Our data demonstrates the significant economic impact of MS on both Brazilian household and health system, in terms of DMTs and other disease management costs. When patients move upwards on the disease severity scale, costs with health resources other than drugs are significantly increased.

Differences in utility scores obtained through Brazilian and UK value sets: a cross-sectional study

Background

Multiple sclerosis (MS) is a chronic disease associated with several impacts; especially regarding patients’ health-related quality of life (HRQL). EuroQol 5 Dimensions questionnaire (EQ-5D) provides self-reported analysis of HRQL and utility scores. Although the British algorithm to convert EQ-5D responses into utility is the most used in the literature, national settings is more appropriate for health policy decision makers. A Brazilian algorithm is available, but not used in MS patients yet. Primarily, this study aimed to address potential differences in utility scores obtained through Brazilian and British value sets. Secondary objective was to determine the role of disability, fatigue and patients socio-demographic and clinical characteristics relevant to MS on the utility scores reported by Brazilian patients.

Methods

Cross-sectional study with MS patients treated in 8 Brazilian sites. Patients were interviewed about socio-demographic and clinical characteristics, self-reported disability level, HRQL and impact of fatigue on daily living. Disability level, HRQL and impact of fatigue were assessed using the Expanded Disability Status Scale (EDSS) and the Brazilian versions of EQ-5D-3L and Modified Fatigue Impact Scale (MFIS-BR), respectively. Patients were classified in subgroups according to EDSS (mild: 0–3; moderate: 4–6.5; severe: >7) and the self-perceived impact of fatigue (absent: ≤38 points; low: 39–58; high: ≥59). EQ-5D-3 L data was converted into a utility index using an algorithm developed by a Brazilian research group (QALY Brazil) and also the UK algorithm. Differences between utility scores were analysed through Wilcoxon test.

Results

Two hundred and ten patients were included in the study. Utility index mean scores of 0.59 (SD = 0.22) and 0.56 (SD = 0.32) for the Brazilian and UK algorithms were observed, respectively, without statistically significant difference for the distribution of data (p = 0.586). However, when utility scores were lower than 0.5, Brazilian algorithm provided higher estimates than UK with a better agreement between the scores found closer to 1. The same trend was observed when data was stratified for EDSS and impact of fatigue, with statistically significant difference between scores in categories of mild/severe disabilities and absent/high impact of fatigue.

Conclusions

Results suggest that Brazilian value set provided higher utility scores than the UK, particularly for measures below 0.5.

Use of Fingolimod in the Management of Relapsing-Remitting Multiple Sclerosis: Experience from Latin America

Once-daily fingolimod 0.5 mg (FTY720; Gilenya(®), Novartis Pharma AG, Basel, Switzerland) is a sphingosine 1-phosphate receptor modulator that is approved for the treatment of relapsing multiple sclerosis (MS); currently, this includes approval in 13 Latin American countries. However, despite a well-characterized efficacy and safety profile in a large clinical development program, thus far there has been limited representation of patients from across the Latin American region. Differences in MS disease characteristics have been reported for the Latin American population compared with Caucasians, which may be additional to recent improvements in MS diagnosis. Furthermore, healthcare provision and regional socioeconomic factors exist that are unique to Latin America compared with other regions. Therefore, to optimize MS treatment pathways and improve patient clinical outcomes, it is important to investigate the efficacy and safety profile of fingolimod using ethnically relevant data. Here, we review key data from Hispanic patients enrolled in the fingolimod clinical trial program, summarize recent findings from the FIRST LATAM study, and appraise fingolimod data from real-world patient populations.

FUNDING

Novartis Pharma AG, Basel, Switzerland.

Deafness in patients with multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disease and is considered the most debilitating neurological disorder among young adults. Sudden deafness has been reported in MS patients. This article describes cases of sudden deafness related to acute bouts in MS patients. A survey was conducted using 405 records of MS patients attended to at a reference center in the city of Rio de Janeiro between 2011 and 2012 to identify cases of sudden deafness. Seven patients were identified, 6 with a relapsing-remitting course and 1 with progressive disease at onset. Five patients had unilateral deafness and 2 bilateral. The recovery was complete in 4 and partial in 1, and there was no recovery in 2 patients. It was not possible to establish a topographical correlation between deafness and brainstem lesions. Audiometric examinations revealed severe hearing loss during the bout and recovery of hearing in 5 cases after remission.

Is it time for a new global classification of multiple sclerosis?

BACKGROUND

The geographic distribution of multiple sclerosis (MS) is classically divided into three zones based on frequency that were established by Kurtzke in the early 1970s. In recent years, an increasing number of epidemiological studies have shown significantly higher MS prevalence and incidence rates.

OBJECTIVE

The aim of this study was to review and update the geographic distribution of MS using incidence, prevalence and disease duration from the latest epidemiology surveys.

METHODS

We conducted a systematic review of articles on MS epidemiology published between January 1, 1990 and December 31, 2012.

RESULTS

MS studies were grouped by continent: the Americas, Europe, Asia, Australia/New Zealand, and Africa. A total of 101 studies were identified according to the inclusion criteria, and 58 reported incidence estimates. Globally, the median estimated incidence of MS was 5.2 (range: 0.5-20.6) per 100,000 p-yrs, the median estimated prevalence of MS was 112.0 (with a range of 5.2-335) per 100,000 p-yrs, and the average disease duration was 20.2 years (range: 7.6-36.2).

CONCLUSION

In the past few decades, the global prevalence and incidence patterns of MS have changed dramatically. Regardless of the reason of increasing prevalence and incidence rate, we suggest the need for a novel classification system based on global MS disease burden. Adopting such a system would improve economic efficiency and prioritization in health policy planning for MS.

Multiple sclerosis care in Latin America

Before the advent of diagnostic criteria for multiple sclerosis (MS), it was reported that the prevalence of MS in Mexico was "one of the lowest in the world" (1.6/100,000).(1) The notion that MS was a rare neurologic disease among those living in the tropics of the Americas and Southern latitudes was widely accepted. The geopolitical boundaries of the region identified as Latin America (LA) extend from the southern border of United States with Mexico (32° North latitude) to the Argentinian and Chilean Patagonia in South America (56° South latitude). The largest Spanish-speaking island countries in the Caribbean-Cuba, Dominican Republic, and Puerto Rico-are also traditionally considered part of LA. The continental mass includes 17 countries with a population of more than 550 million. Due to centuries of racial intermixing, it is a heterogeneous and genetically complex population. The blended cultures of native Amerindians with white Caucasian Europeans and black Africans has resulted in the predominant ethnic Latin American Mestizo. The influence of African genetics is notable in many areas of the subcontinent and the Caribbean. A common observation across LA is the absence of identification of MS in non-mixed Amerindians(2); the reason for this phenomenon is unclear.