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Epidemiology of Multiple Sclerosis in Latin America: Critical Analysis of the Literature

      Objectives

      To summarize rates of prevalence, incidence and types of multiple sclerosis (MS) in Latin America.

      Methods

      We searched Medline, Embase, Scielo and LILACS using key words “multiple sclerosis” and “esclerosis múltiple”, plus “Latin America” and all country names. Accepted were full articles or abstracts reporting original research in any language at any time, with MS diagnosed using any acceptable criteria. Clinically isolated syndrome was excluded.

      Results

      1482 articles were identified and 203 reviewed in full; 88 were rejected and 115 were analyzed (38 prevalence, 3 incidence, 2 both, 72 clinical epidemiology), including 68 (59%) full text and 47 (41%) abstracts. Studies originated in 14 countries, mostly larger, more affluent nations (47% Brazil, 15% Argentina, 8% Mexico). Prevalence studies examined 19,357 MS cases from 1968-2012; rates ranged from 0 in a group of Mexican natives to 52/100,000 in Puerto Rico, with a mean of 13.9/100,000. This range would be classified as low to medium, with 83,000 (CI95%: 62,000-104,000) prevalent cases in Latin America. Incidences ranged from 0.15/100,000 person-years in Panama to 1.76 in Argentina (median=1.32, mean=1.35), or 7,887-8,365 new cases/year in Latin America. Authors noted increasing prevalence and incidence rates over time. Clinical epidemiology MS data were obtained from 94 studies; 66% used Poser criteria, 48% McDonald (various versions), and 14% other, from 19,893 patients (72% females). The average age at assessment was 38.2 and 32.2 at disease onset with average EDSS of 3.1. The relapsing-remitting form was most prevalent (74% of cases), followed by secondary progressive (12%) and primary progressive (10%).

      Conclusions

      MS prevalence and incidence rates vary widely in Latin America in a low to medium range, but are increasing as reported in the reviewed studies. Information is scant with many gaps. More research is needed to provide a basis for decision making and budget allocation.