Predicting the profile of increasing disability in multiple sclerosis

BACKGROUND: Effective therapeutic strategies to preserve function and delay progression in multiple sclerosis (MS) require early recognition of individual disease trajectories. OBJECTIVES: To determine the profiles of disability evolution, identify their early predictors and develop a risk score of increasing disability. METHODS: We analysed demographic, clinical and magnetic resonance imaging (MRI) data from patients with relapsing MS, Expanded Disability Status Scale (EDSS) score of 3.0–4.0 and follow-up ≥ 2 years. Attaining EDSS = 6.0 defined increasing disability; relapses and/or MRI defined disease activity. RESULTS: In total, 344 out of 542 (63.5%) patients reached EDSS ≥ 6.0; of these, 220 (64.0%) showed disease activity. In patients with activity, the number of relapses before reaching EDSS 3.0–4.0 predicted increasing disability; age > 45 at baseline predicted increasing disability without activity. Combining age and number of relapses increased the risk of and shortened the time to EDSS = 6.0. CONCLUSION: Increasing disability is frequently associated with persistent activity. The high number of relapses identifies early those patients worsening in the presence of activity. Age predicts increasing disability in the absence of activity. The presence of both factors increases the risk of developing severe disability. As this study likely describes the transition to progression, our findings contribute to improving patient management and stratification in trials on progressive MS.