# Adult-onset and late-onset multiple sclerosis in older adults in a Finnish university hospital

## TL;DR

This study compares late-onset and adult-onset multiple sclerosis in older adults, finding that late-onset cases are more likely to be primary progressive and experience relapses later in life.

## Contribution

The study provides new insights into the clinical differences between late-onset and adult-onset MS in older adults.

## Key findings

- Late-onset MS is more commonly primary progressive compared to adult-onset MS.
- Relapses after age 65 occurred in a small percentage of both groups, with no significant age-related disability differences.
- Late-onset MS patients discontinued disease-modifying therapy at an older age than adult-onset MS patients.

## Abstract

The clinical characteristics of multiple sclerosis (MS) in individuals aged 65 years and older remain scarcely studied. This retrospective study compared late-onset MS (LOMS, onset ≥ 50 years) and adult-onset MS (AOMS, onset 18–49 years) in older adults with MS (OAwMS) aged ≥ 65 years.

Data of subjects aged ≥ 65 years with a confirmed MS diagnosis and a recorded age at onset were collected from the Finnish MS registry at Tampere University Hospital, excluding individuals with paediatric-onset MS. Demographics, disease-modifying therapy (DMT) use, relapse history and Expanded Disability Status Scale (EDSS) scores were compared between LOMS and AOMS groups.

The cohort included 248 subjects (41 LOMS, 207 AOMS). Primary progressive MS (PPMS) was more common in LOMS when compared to AOMS (41.5% vs. 12.6% at data acquisition, p < 0.001). Among subjects with a history of relapsing-remitting MS (RRMS) (32 LOMS, 178 AOMS), DMT had been used by 25.0% and 27.5% of subjects with LOMS and AOMS, and relapses after age 65 occurred in 18.8% and 7.3% of subjects with LOMS and AOMS, respectively. Subjects with LOMS discontinued DMT at an older age when compared to those with AOMS (mean 64.0 vs. 58.8 years, p = 0.04). No age-related differences in EDSS were observed after age 65.

PPMS was more common among subjects with LOMS. Among subjects with a current or previous diagnosis of RRMS, occasional relapses were observed after age 65 in both groups, though multiple relapses were rare. These findings support the need for individualised care of OAwMS.