Silent progression in disease activity-free relapsing multiple sclerosis.

Area of Science:

• Neurology
• Neuroimmunology
• Clinical Neuroscience

Background:

• Relapsing multiple sclerosis (MS) management aims to prevent disability accumulation.
• Despite active treatment, many relapsing MS patients experience significant disability progression over time.
• No evidence of disease activity at two years does not guarantee long-term stability.

Purpose of the Study:

• To investigate the contribution of clinical relapses and radiographic disease activity to long-term disability accumulation in relapsing MS.
• To identify factors driving progressive disability in patients with relapsing MS.
• To characterize the phenomenon of "silent progression" in multiple sclerosis.

Main Methods:

• Defined disability progression based on sustained increases in Expanded Disability Status Scale (EDSS) scores over 10 years.
• Utilized longitudinal analysis of relative brain volume loss.
• Employed linear mixed models, accounting for sex, age, disease duration, and HLA-DRB1*15:01 status.

Main Results:

• Clinical relapses were associated with transient, but not confirmed, disability increases.
• Accelerated brain atrophy (relative brain volume loss) was observed in patients with disability progression.
• Disability progression was significantly associated with greater rates of brain volume decline (p < 0.05).

Conclusions:

• Long-term disability worsening in relapsing MS is common and largely independent of clinical relapse activity.
• Accelerated brain atrophy is a key feature associated with progressive disability in MS.
• The concept of "silent progression" is proposed for insidious disability accrual in relapsing-remitting MS patients.