Improved ability to work after one year of natalizumab treatment in multiple sclerosis. Analysis of disease-specific and work-related factors that influence the effect of treatment

Background: Multiple sclerosis (MS) constitutes one of the major diseases that leads to neurological impairment and as a consequence also reduces ability to work. Objectives: The purpose of this study was to analyze possible effects on work ability resulting from highly active anti-inflammatory treatment in MS. Methods: We analyzed the effects of introducing an anti-inflammatory treatment, natalizumab, in MS, on factors related to work ability. This was done through a comprehensive questionnaire distributed to all patients in Sweden starting on natalizumab treatment between June 2007 and May 2008, identified via the Swedish National MS registry. Results: MS patients who were receiving sickness benefit and were treated with natalizumab approximately doubled their working ability in relation to their total employment rate. We also documented a significant improvement of their ability to cope with work-related requirements after one year of natalizumab treatment, an improvement which was independent of the previous level of employment. Predictors of a positive effect on work ability were short disease duration, younger age and lower Expanded Disability Status Scale (EDSS) grade at treatment onset. Conclusions: Our data support the notion that early inflammatory control in MS is essential to preserve a healthy state in MS that counteracts the negative consequences of the disease both at a personal and at a societal level.