Incidence of multiple sclerosis in Chile. A hospital registry study

Multiple sclerosis in Central America and Caribbean countries: frequency and clinical characterization of an emergent disease

Background

Multiple Sclerosis (MS) is a common neurological disease among white populations of European origin. Frequencies among Latin Americans continue to be studied, however, epidemiologic, and clinical characterization studies lack from Central American and Caribbean countries. Ethnicity in these countries is uniformly similar with a prevalent Mestizo population.

Methods and results

Data from January 2014 to December 2019 from Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Dominican Republic, and Aruba on demographic, clinical, MRI and phenotypic traits were determined in coordinated studies: ENHANCE, a population-based, retrospective, observational study on incidence and clinical characteristics, and from the subgroup with MS national registries (Aruba, Dominican Republic, Honduras, and Panama), data on prevalence, phenotypes and demographics. Expanded Disability Status Scale (EDSS), and therapeutic schemes were included. ENHANCE data from 758 patients disclosed 79.8% of Mestizo ethnicity; 72.4% female; median age at onset 31.0 years and 33.2 at diagnosis. The highest incidence rate was from Aruba, 2.3-3.5 × 100,000 inhabitants, and the lowest, 0.07-0.15 × 100,000, from Honduras. Crude prevalence rates per 100,000 inhabitants fluctuated from 27.3 (Aruba) to 1.0 (Honduras). Relapsing MS accounted for 87.4% of cases; EDSS <3.0 determined in 66.6% (mean disease duration: 9.1 years, SD ± 5.0); CSF oligoclonal bands 85.7%, and 87% of subjects hydroxyvitamin D deficient. Common initial therapies were interferon and fingolimod. Switching from interferon to fingolimod was the most common escalation step. The COVID-19 pandemic affected follow-up aspects of these studies.

Conclusion

This is the first study providing data on frequencies and clinical characteristics from 8 countries from the Central American and Caribbean region, addressing MS as an emergent epidemiologic disorder. More studies from these areas are encouraged.

Multiple sclerosis in indigenous peoples of the Americas: A systematic review of incidence, prevalence, and outcomes

INTRODUCTION

The incidence, prevalence and outcomes of multiple sclerosis (MS) are unclear in Indigenous Peoples (IP) who are more likely to be underrepresented in research. We completed a systematic review of MS in IP of the Americas.

METHODS

A systematic review was conducted using PubMed, Web of Science, and Cochrane databases as well as references of retrieved papers. Inclusion criteria were: peer-reviewed publications (January 1990- December 2021), incidence, prevalence, or clinical outcome measures of MS in self-identified IP in the Americas. Incidence, prevalence, morbidity and mortality data were summarized and stratified by location and year of publication. Study quality was evaluated by risk of bias or confounding.

RESULTS

Out of 416 titles, thirteen studies met inclusion criteria. Four studies evaluated incidence, seven prevalence, three clinical outcomes and one mortality. Most studies were completed in Canada or the United States (US). Incidence rates per 100,000 ranged from 0.48 (in US Indian Health Service records) to 8.15 (First Nations Manitoban Canadians). Prevalence ranged from 0 (Lacandonian Mexicans and Panamanians) to 188.5 (First Nations Manitoban Canadians). Incidence and prevalence are consistently lower in IP than comparator White populations. IP with MS were reported to have higher disability and faster disability progression than non-Indigenous comparators. MS-related mortality is low compared to White people.

CONCLUSION

There is an absence of high-quality studies evaluating MS in IP. Available evidence indicates low, but increasing incidence and prevalence of MS in IP of the Americas. IP with MS may have worse disability than non-Indigenous comparators. Future studies should evaluate the factors influencing the increases in incidence and prevalence as well as better characterize possible disparities in MS care among IP.

Inclusion of the Symbol Digit Modalities Test in a revised assessment of 'no evidence of disease activity-4 (NEDA-4)' in Latin-American patients with multiple sclerosis

BACKGROUND

In relapsing-remitting multiple sclerosis (RRMS), no evidence of disease activity-3 (NEDA-3) is defined as the absence of: (1) relapses; (2) disability progression; (3) MRI activity (new/enlarged T2 lesions and/or gadolinium-enhanced T1 lesions). NEDA-4 status is defined as meeting all NEDA-3 criteria plus having an annualized percentage brain volume change (a-PBVC) >-0.4%. In individual patients, brain volume assessment is confounded with normal aging, methodological limitations and fluid-shift related fluctuations in brain volume. Cognitive impairment has been proposed as another component that should be integrated into therapeutic algorithms for RRMS. We aim to determine the proportion of patients failing to meet NEDA-4 criteria and to appraise whether the Symbol Digit Modalities Test (SDMT) is capable of replacing a-PBVC as one of the components of NEDA-4. We hypothesize that NEDA-4 has the potential to capture the impact of DMT therapies in RRMS.

METHODS

Forty-five patients were prospectively followed 1 and 2 years after their baseline assessment at the University of Chile Hospital. SIENA software was used to assess a-PBVC.

RESULTS

At baseline, the patients had a mean age of 33.0 years (range 18-57), disease duration of 1.9 years (0.4-4), Expanded Disability Status Scale score of 1.3 (0-4), and 67% were female. The majority had RRMS (91% while 9% had clinically isolated syndrome (CIS)). Seventy-three percent were on the so-called first line DMTs such as interferons (53%), glatiramer acetate (13%), teriflunomide (9%), and 18% were on fingolimod. There was a serial decline in the proportion of NEDA: after 1 and 2 years of follow-up 60% and 47% met NEDA-3 status, and 38% and 27% met NEDA-4, respectively. At the last follow-up 21% remained on interferons, 47% were now on fingolimod, 4% on alemtuzumab and 2% on natalizumab. At year 1 and year 2, with the replacement of a-PBVC by SDMT, 53% and 40% of patients achieved a putative NEDA-4 status, respectively.

CONCLUSION

Brain volumetric MRI has yet to be translated into clinical practice and SDMT may qualify as the fourth component of NEDA-4 definition. NEDA-4 has the potential to capture the impact of DMT therapies in RRMS earlier in the disease course of RRMS.

Vitamin D and multiple sclerosis—from epidemiology to prevention

In the present review, we discuss observational and experimental data suggesting a protective effect from sun exposure and/or vitamin D in multiple sclerosis (MS). These data include geographic variations in MS occurrence, temporal trends, genetics, biobank, and questionnaire data. We look more closely at the differentiation between general effects from UV exposure, and those of vitamin D per se, including plausible mechanisms of action. Finally, primary prevention is touched upon, and we suggest actions to be taken while awaiting the results from ongoing randomized controlled trials with vitamin D in MS.

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.

The epidemiology of multiple sclerosis in Latin America and the Caribbean: a systematic review

The incidence and prevalence of multiple sclerosis (MS) varies geographically as shown through extensive epidemiological studies performed mainly in developed countries. Nonetheless, scant data is available in Latin America and the Caribbean (LAC). The objective of this review is to assess epidemiological data of MS in LAC. We conducted a systematic review of published articles and gray literature from January 1995 to May 2011. Twenty-two studies met the inclusion criteria after full-text review. Incidence data were found in only three studies and ranged from 0.3 to 1.9 annual cases per 100,000 person-years. Prevalence was reported in 10 studies and ranged from 0.83 to 21.5 cases per 100,000 inhabitants. The most prevalent subtype of MS was the relapsing–remitting form (48% to 91% of the series). No data about mortality were found. This study showed low frequency for MS in LAC compared with North American and European countries. The role of environmental and genetic factors should be well studied, providing new insights about its etiology.