Characterization of a late-onset multiple sclerosis Portuguese cohort.

BACKGROUND:Late-onset multiple sclerosis (LOMS) is defined as the onset of symptoms above 50 years, corresponding to an increasingly recognized subset of MS. This study aimed at comparing demographic and clinical data of patients with LOMS to those of early-onset MS (EOMS) from a Portuguese cohort. METHODS:Retrospective chart review of an MS cohort from a Portuguese tertiary center. RESULTS:From 746 patients with MS (61.7% female), we identified 39 cases with presentation after 50 years of age (22 males and 17 females), corresponding to 5.3%. The mean age at onset was 55.4 (±5.0) for LOMS and 29.5 (±8.9) for EOMS. There was no significant difference in disease duration. The most common type was relapsing-remitting MS, accounting for 51.5% and 83.9% of LOMS and EOMS patients, respectively. Primary-progressive MS (PPMS) was significantly more represented in the LOMS group (41.0%) (p < 0.01). The median EDSS was significantly higher in the LOMS group (4.75, 0.0-7.5) when compared to the EOMS group (2.0, 0.0-9,0). The most frequent presenting feature was myelitis in both LOMS (48.7%) and EOMS patients (47.4%), resulting in significantly higher EDSS (p = 0.003). CONCLUSIONS:LOMS is associated with higher EDSS when considering the same disease duration, translating into increased disability.