Epidemiology of Multiple Sclerosis: Literature Review for Prevalence and Trend Over Time in 5 European Countries and Canada

OBJECTIVES: To analyze and compare published prevalence rates and trends over time for multiple sclerosis (MS) and predict patient numbers in 2017. METHODS: Systematic search (1990-2017 May) in Medline, Embase, back-referencing and additional searches in Registries / HTA websites/ Health Insurers. Key words: "multiple sclerosis; epidemiology, prevalence". Inclusion criteria: published after 1989; prevalence reported, all kinds of observational studies, country of interest, no language-restriction. Based on retrieved data yearly increase (absolute and relative to year 2016) was calculated and patient numbers for 2017 were predicted. RESULTS: 98 full text articles and two public available health claims databases [Statutory health insurance (SHI) Germany and France] were included. Prevalence rate/lOOk, number (#) of MS patients and yearly absolute/relative increase of prevalence rate, based on a linear trend (if not indicated otherwise) were as follows: France: 143/100k; #88,600; 3.8/2.8% [SHI France 2008-2015] and 2.6/1.7% [7 articles 2003-2015]; Germany: 310/100k, #245,400; 10/3.4% [SHI 2011-2017] and 7.2/2.5% [8 articles 1990-2010]; Italy: 149/100k (weighted average by sample size), #86,100; 5.6/2.7% [37 articles 1990-2010]; Spain. 104/100k (weighted average by sample size), #50,400, 2.3/2.4% [29 articles 1991-2014]; UK: 147/lOOk, #110,100; 3.3/1.9% [6 articles 1993-2013]; Canada: 267/100k, # 81,900; 4.5/1.7% [11 articles 1990-2010]. All included countries showed an increase of prevalence rate over the last decades whereas incidence was only slightly increasing and mortality decreased (data not shown). Health claims data provided the most recent data and report more patients compared to the published literature. Additional reasons for increased prevalence are discussed and include new diagnostic criteria since 2010, increased awareness, migration as well as Vitamin D level. CONCLUSIONS: MS prevalence varies widely within regions but increased comparable by 2-4% per year in Europe and Canada, whereas incidence increased only slightly for the last 5 years. Additional research for risk factors for MS should be undertaken.