Disease Activity and Progression of Disability in Multiple Sclerosis Patients Aged Over 50 With or Without Disease-Modifying Drug Treatment: A Retrospective Cohort Study.

Background This study aimed to clarify the need for disease-modifying drug (DMD) treatment in elderly patients with multiple sclerosis (MS) aged 50 years or older. MS is an autoimmune, demyelinating disease of the central nervous system that predominantly affects young women. Various DMDs are effective in preventing relapses and slowing the progression of disability in patients with MS. Although disease activity in MS is believed to decrease with aging, a consensus on the appropriate DMD treatment for elderly patients with MS is lacking. Methodology This study included elderly patients with MS (>50 years old). We compared the occurrence of relapses, worsening of disability, and conversion to secondary progressive MS (SPMS) between patients with DMD treatment and those without. Logistic regression analysis was performed to determine the predictors of these outcomes. Confounding factors were adjusted using propensity scores. Results From January 1991 to October 2022, 76 elderly patients with MS were included. The mean age at the last visit was 57.4 ± 6.3 years, with 51 patients being female. The mean age of onset of MS was 37.1 ± 10.1 years. Fifty-four patients were included in the DMD treatment group. The overall relapse rate was 38% (33% and 48% in the DMD treatment and untreated groups, respectively). No significant differences in relapse rates (p = 0.72) or in the Expanded Disability Status Scale (EDSS) scores were identified between the two groups. Kaplan-Meier curves showed no differences in the time to first relapse within five years between the two groups. Additionally, no significant predictors of relapse were identified. Among 61 patients with relapsing-remitting MS, 25% converted to SPMS during the observation period. Logistic regression analysis showed that older age at the final visit and the presence of brainstem lesions at the age of 50 years were associated with a higher rate of transition to SPMS. Conclusions In the present study, no significant difference was found in the rate of relapse, disability progression, and conversion to SPMS between the DMD treatment and untreated groups in elderly patients with MS. Therefore, in patients without long-term relapse, no poor prognostic functional factors or predictors of conversion to SPMS, discontinuation of DMDs may be considered. In addition, the presence of brainstem lesions at 50 years of age may predict the conversion to SPMS. Thus, the continuation of DMD or conversion to an appropriate DMD should be considered in patients with brainstem lesions at 50 years of age.