Natural history of multiple sclerosis in a population-based cohort

We sought to identify predictive clinical factors of disability during initial course in multiple sclerosis (MS) patients. A total of 2871 MS patients from the LORSEP (Lorraine Multiple Sclerosis) population-based cohort were analyzed. The relationships between baseline demographic, clinical predictors and time to assignment of Expanded Disability Status Scale (EDSS) scores of 3, 4 and 6 were assessed using a Cox regression model. Multivariate analysis showed that, for relapsing-remitting patients, a shorter time to assignment of an EDSS score of 4 was associated with an older age of onset of MS and incomplete recovery from the first relapse. Median times were not influenced by gender or the time between the first two relapses. The results also demonstrated that MS progression is independent of the initial clinical data once an EDSS score of 4 is reached rather than a score of 3 because the time from EDSS 3 to assignment of EDSS 4 were correlated with predicting variables. The data were very different for the time between assignment of scores of 4 and 6 because the median times were not influenced by any of the predicting variables.