Late-onset versus adult-onset multiple sclerosis: A comparative analysis of clinical, radiological, and confirmed disability progression.

Background

Multiple sclerosis (MS) is a chronic, immune-mediated disorder of the central nervous system (CNS). In Egypt, its occurrence is approximately 13.7 per 100,000 inhabitants. The average age of onset for relapsing-remitting MS (RRMS) is between the second and fourth decades of life.

Objectives

To determine the differences in clinical characteristics, disease course, and progression between adult-onset MS (AOMS) and late-onset MS (LOMS). SUBJECTS AND

Methods

This observational comparative study was conducted on patients diagnosed with MS according to the revised McDonald criteria at the MS Clinic of Kasr Al-Ainy Hospital, Cairo University. Patients with AOMS (111) and LOMS (54) were compared based on various parameters, with longitudinal assessment of disease progression.

Results

The LOMS group had a significantly higher proportion of patients with primary progressive MS (PPMS) than the AOMS group. Additionally, the LOMS group had significantly fewer relapses, a lower annualized relapse rate (ARR), a longer disease duration and longer time to treatment, and a higher baseline EDSS score than the AOMS group (P < 0.05). Regarding baseline brain MRI findings, a higher percentage of LOMS patients had infratentorial lesions (P = 0.0002). LOMS patients also experienced earlier confirmed disability progression (CDP). The median time to CDP was 71 months (95% CI, 31.7-94.4) in the LOMS group and 113.6 months (95% CI, 81.2-142.0) in the AOMS group. In a stepwise Cox proportional hazards regression analysis, LOMS status remained significantly associated with CDP, (HR = 1.89, 95% CI 1.05-3.42, P = 0.035), indicating an approximately 89% higher risk of CDP compared with AOMS.

Conclusion

The present study adds data from an Egyptian cohort and highlights significant differences between AOMS and LOMS. Patients with LOMS tend to have a higher prevalence of PPMS, a greater burden of comorbidities, higher baseline disability, lower relapse activity, and a shorter time to CDP.