Multiple sclerosis relapses: a multivariable analysis of residual disability determinants

Recovery from multiple sclerosis (MS) relapses is variable. The factors influencing persistence of residual disability (RD) after a relapse are still to be thoroughly elucidated. To assess RD after MS relapses and to define the factors associated with persistence of RD. Data were retrospectively collected for all relapses in a population of relapsing-remitting MS patients during 3 years. Relapse severity and RD after 1 year were calculated on Expanded Disability Status Scale basis. A multivariable analysis for factors influencing RD and relapse severity was performed (variables: age, gender, disease duration, oligoclonal bands, relapse severity, monosymptomatic/polysymptomatic relapse, immunomodulating treatment, incomplete recovery at 1 month). A total of 174 relapses were assessed. RD after 1 year was observed in 54.5% of the relapses. Higher risk of RD was associated with occurrence of a severe relapse (P = 0.024). Incomplete recovery at 1 month was highly predictive of RD at 1 year (P < 0.0001). Risk of a severe relapse was associated with age <= 30 years (P = 0.025) and inversely associated with the use of immunomodulating treatment (P = 0.006). Incomplete recovery at 1 month is a predictor of long-term persistence of RD. Higher relapse severity is associated with higher risk of RD. Risk of severe relapses is lower in patients treated with immunomodulating drugs.