ABSTRACT
The worldwide incidence of multiple sclerosis (MS) is estimated at 0.5-10 cases per 100.000 personyears and is probably increasing. Incidence in Uruguay was estimated in 1.2 cases per 100.000 personyears in a 2015 study. Following the EMELAC protocol (MS in Latin America and Caribbean region), we conducted an observational, prospective, population-based study to determine MS incidence in Uruguay. The population under study included people living in Uruguay between 7-1-2019 and 6-30- 2021, with18 years and above. The diagnosis was based on the 2017 McDonald criteria. Multiple data sources were employed. All possible cases of MS were reviewed by the research team. Cases with diagnostic uncertainty were re-reviewed by an outside co-author (D.O.). Results: 155 new MS cases were confirmed after review including 111 females (71.6 %). 99 of them were examined directly by the research team (63.9 %). The sex ratio was 2.5:1 female/male. Age range was 18 to 62. Median age was 33 years and the standard deviation 11.4 years. 111 (71.6 %) cases were relapsing-remitting MS, 9 (5.8 %) primary progressive MS and 2 secondary progressive MS. We have no data in 33 cases (21 %). Global incidence rate was 2.88 cases per 100.000 person-years, 3.95 in females and 1.72 in males. The highest incidence was observed in the group with 35-39 years (5.28 cases per 100.000 personyears). Discussion: According to MS Atlas, Uruguay has a low incidence rate (2.0-3.99). Despite this, the MS incidence in Uruguay is one of the highest in Latin America. Age and gender distribution were similar to other studies. We found a lower proportion of primary progressive MS. COVID19 pandemic raised methodological problems which could have led to an underestimation of the incidence.
ABSTRACT
Introduction: The worldwide incidence of multiple sclerosis (MS) is estimated to be 0.5-10 cases per 100.000 person-years and is probably increasing. Incidence in Uruguay was estimated in 1.2 cases per 100.000 person-years in a 2015 study. Objectives: To determine MS incidence in Uruguay Methods: Following the EMELAC protocol (MS in Latin America and Caribbean region), we conducted an observational, prospective, population based study to determine MS incidence in Uruguay. The population studied included people living in Uruguay, older than 18 years of age, between 7-1-2019 and 6-30-2021. The diagnosis was based on the 2017 McDonald criteria. Multiple data sources were employed. All possible cases of MS were reviewed by the research team. Cases with diagnostic uncertainty were re-reviewed by an outside coauthor (D.O.). Results: 137 new MS cases were confirmed after review including 100 females (73%). 65 of them were examined directly by the research team (47%). The sex ratio was 2.7:1 female/male. Age range was 18 to 62 with a median of 35 and an interquartile range of 16.5 (26.5-43). 129 (94%) cases were relapsing-remitting MS, 7 (5%) primary progressive MS and 1 secondary progressive MS. Global incidence rate was 2.55 cases per 100.000 person-years, 3.55 in females and 1.45 in males. The highest incidence was observed in the 35-39 years old group (5.28 cases per 100.000 person-years). Conclusions: According to MS Atlas, Uruguay has a low incidence rate (2.0-3.99). Despite this, the MS incidence in Uruguay is one of the highest in Latin America. Age and gender distribution were similar to other studies. We found a lower proportion of primary progressive MS. COVID19 pandemic raised methodological problems which could have led to an underestimation of the incidence. These preliminary results will be completed in upcoming publications.