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.

Prevalence of stroke in an Argentine community.

OBJECTIVE: To determine the prevalence of stroke and its distribution by age, sex and clinical type, and to use the outcomes for prevention, care and rehabilitation. DESIGN/METHOD: The survey was conducted in Junín, a town of about 75,000 inhabitants, situated in an agricultural region of the Province of Buenos Aires, Argentina. Systematic sampling was used to select 5,839 dwellings (sampling fraction approximately 25%) and 5,648 (97%) households participated in our study, including 17,049 participants. The initial stage of the study involved a case-finding strategy consisting of a two-stage screening approach in the selected households; household screening was followed by neurological examination. We used a point prevalence with reference date January 1, 1991. Stroke was defined according to the WHO criteria. RESULTS: As of January 1, 1991, 148 subjects were identified as cases of stroke (79.6% ischemic and 20.4% hemorrhagic). Point prevalence ratio was 868.1 cases per 100,000 inhabitants in the total population (473.4/100,000 age adjusted to the worldwide population) and 1,867.4 in those patients of 40 years of age or older (1,534.4/100,000 age adjusted to the worldwide population). In both sexes, prevalence increased with age. However, this increase was more significant and sustained in men of 50 years of age and older. Moderate to severe disability was observed in 52% of patients. CONCLUSION: This is one of the first community-based studies conducted in Argentina about the prevalence of stroke. Final results are similar to those reported in other developed countries.