Prevalence of multiple sclerosis in key cities of Brazil: a study in Passo Fundo, Southern Brazil

To improve the comparability of multiple sclerosis (MS) prevalence across Brazilian regions, the Brazilian Committee for Treatment and Research in MS has implemented a standardized approach to assess the prevalence of the disease in five key cities, which were deemed representative of their regions in terms of socio-geographical features and where in-person revision of each case was feasible.

To report the point-prevalence of MS in Passo Fundo, one of the key cities in Southern Brazil.

We sought to identify all MS patients who were living in Passo Fundo on July 1st, 2015. The primary source for case ascertainment was records from the offices of neurologists and neurosurgeons practicing in the city. Multiple secondary sources were used to maximize identification of cases. All patients underwent in-person review of the diagnosis by a panel of neurologists with experience in MS.

We identified 52 MS patients living in Passo Fundo on July 1st, 2015. The point-prevalence rate for MS was 26.4/100,000 population (95% confidence interval, 19.7 to 34.6/100,000). Among the MS cases, 42 (80.8%) were female, for a sex ratio of 4.2:1. Forty-six cases (88.5%) were categorized as relapsing-remitting MS, and the remaining 6 cases, as secondary progressive MS (11.5%). Other epidemiological and clinical features were comparable to national and international MS populations.

The prevalence of MS in Passo Fundo is one of the highest reported in Brazil so far. Studies in other key Brazilian cities, using the same methodology, are currently being carried out.