Late-onset MS is associated with an increased rate of reaching disability milestones

To describe patient characteristics and assess the risk of disability worsening in patients of different age groups with focus on late-onset multiple sclerosis (LOMS) defined as disease onset after the age of 50 years.

The nationwide population-based Danish Multiple Sclerosis Registry served as data source. We described baseline characteristics and analyzed rates of reaching Expanded Disability Status Scale (EDSS) milestones.

We identified 28,232 patients with MS with a known year of clinical onset, of which 2661 had LOMS. The LOMS group had a higher proportion of males and patients with primary progressive disease course, and they were less likely to receive disease-modifying therapy. The initial rate of reaching EDSS milestone 6 after diagnosis was higher in LOMS [hazard ratio (HR) 1.53; 95% confidence interval (CI) 1.14-2.06]; however, when assessing the risk of reaching EDSS 6 according to age, the HR was significantly lower for the LOMS group (HR 0.307; 95% CI 0.221-0.426).

The clinical characteristics and treatment approaches for patients with LOMS differ from their younger counterparts. Following diagnosis, patients with LOMS initially have an increased rate of reaching EDSS score 6; however, the risk of reaching EDSS score 6 at any given age is higher in patients with non-LOMS.