Assessing long-term prognosis improvement as a consequence of treatment pattern changes in MS

Objective: To assess whether the age at which multiple sclerosis (MS) patients reach Expanded Disability Status Scale (EDSS) milestones changed as long as new drugs for the treatment of MS became available. Methods: We evaluated the long-term impact of therapies on disability progression assessing whether there is a detectable delay in the age at which patients reached EDSS milestones in more recent years. We used data collected over more than 30 years in the Center of Brescia, Italy. We compared the age at EDSS = 6 among patients diagnosed with relapsing-remitting MS in different time periods, adjusting for age at diagnosis and median interval among EDSS visits, by a multivariate Cox model. Results: A total of 1324 MS patients were included. Patients diagnosed in more recent periods reached EDSS = 6 at an older age: the rate at which patients reached EDSS = 6 in those diagnosed in 1991-1995 was similar to those diagnosed in 1980-1990 (hazard ratio (HR) = 1.09, p = 0.68) and to those diagnosed in 1996-2000 (HR = 0.85, p = 0.44), it was reduced by 37% in patients diagnosed in 2001-2005 (HR = 0.63, p = 0.05), by 46% in patients diagnosed in 2006-2010 (HR = 0.54, p < 0.02). Conclusion: A clear modification of MS course is observed after 2000; among other causes, this can be associated to the changes in the treatment patterns experienced in those years.