The following is a summary of “Clinical Characteristics and Long-Term Outcomes of Late-Onset Multiple Sclerosis,” published in the February 2024 issue of Neurology by Mouresan et al.

The rare occurrence of clinical onset of multiple sclerosis (MS) after age 50 is linked with a less favorable progression. However, there’s a gap in understanding the contrasting long-term outcomes between late-onset MS (LOMS, onset at 50 years or older) and adult-onset MS (AOMS, onset between 18 and 49 years) in the era of disease-modifying therapy (DMT).

Researchers conducted a retrospective study to assess and contrast patient characteristics, exposure to DMT, and disability progression among Swedish patients with LOMS and AOMS over two decades (2001–2022).

They searched the nationwide Swedish MS registry for individuals with MS onset (January 1, 2001- December 31, 2018), aged 18 years or older, and with at least two documented Expanded Disability Status Scale (EDSS) scores. Clinical and demographic data and exposure to DMT were compared between LOMS and AOMS. Time to reach disability milestones (EDSS 4 and 6) was evaluated using Kaplan-Meier curves and Cox proportional hazards regression models, adjusted for sex, disease course, calendar year at onset, and DMT exposure.

The results showed that among the 8,739 patients with MS meeting the inclusion criteria, 1,028 (11.8%) were classified as LOMS. A higher incidence of primary progressive MS was observed in LOMS compared to AOMS (25.2% vs 4.5%; P<0.001). Most patients were prescribed DMT, although less frequently in LOMS than in AOMS (74.7% vs 95.6%; P<0.001). High-efficacy DMT exposure was lower in LOMS than AOMS (45.8% vs 73.5%; P<0.001). The risk of reaching disability milestones was significantly higher in LOMS compared to AOMS (EDSS 4; adjusted HR [aHR] 2.71; 95% CI 2.22–3.30; P<0.001, and EDSS 6; aHR 2.67; 95% CI 2.12–3.36; P<0.001).

Investigators concluded that the study identified LOMS as a high-risk group for MS complications and suggested further research on DMT benefits in older adults with MS.

Source: neurology.org/doi/10.1212/WNL.0000000000208051