From youth to late age: a comparative analysis of clinical and demographic profiles in multiple sclerosis by age at onset.

Purpose: This study aimed to compare clinical and demographic characteristics, treatment approaches, and comorbidities among multiple sclerosis (MS) patients with pediatric-onset (POMS), adult-onset (AOMS), and late-onset multiple sclerosis (LOMS). METHODS: We analyzed the medical records of 439 patients diagnosed with MS, hospitalized between 2018 and 2023 in the University Clinical Center, Medical University of Silesia. The patients were divided into categories based on their age at onset: POMS - < 18 years, AOMS - 18-49 years, and LOMS - ≥ 50 years. Age of onset, symptoms, age at diagnosis, diagnostic delay, Expanded Disability Status Scale (EDSS) scores, course of the disease, relapse characteristics, comorbidities, and use of disease-modifying therapy were compared between the groups. Results: The LOMS group was characterized by a higher proportion of males, had the longest diagnostic delay and disease duration, highest comorbidity rates, and a greater level of disability. Median EDSS score was highest in the LOMS group (3.16) and lowest in the POMS (0.73) (p < 0.001). Relapsing-remitting MS was most prevalent in the POMS and AOMS groups, while progressive MS was more prevalent in LOMS (p < 0.001). The longest first-line therapy durations and the lowest rate of switching to second-line therapies were observed in the LOMS group. Conclusions: Characteristics of MS vary, based on the age of onset, hence every patient requires a personalized approach. The higher prevalence of the progressive form, more frequent comorbidities and higher degree of disability observed in the LOMS group makes treatment of this group more challenging and treatment switching is more frequent.