Risk Factors and Time to Clinical Symptoms of Multiple Sclerosis Among Patients With Radiologically Isolated Syndrome

Area of Science:

• Neurology
• Neuroimmunology
• Radiology

Background:

• Radiologically isolated syndrome (RIS) presents diagnostic challenges, with variable conversion rates to multiple sclerosis (MS).
• Identifying early predictors of MS conversion in RIS is critical for timely therapeutic intervention.
• The efficacy of disease-modifying therapies in the RIS stage remains largely unestablished.

Purpose of the Study:

• To prospectively assess the 2-year risk of clinical conversion from RIS to MS.
• To identify specific factors associated with early clinical events in individuals with RIS.
• To estimate the sample size required for phase III clinical trials in this population.

Main Methods:

• A prospective cohort study of individuals diagnosed with RIS based on 2009 criteria.
• Data collected from 26 French tertiary MS care centers, including detailed MRI and clinical follow-up.
• Multivariate analysis to identify independent predictors of clinical conversion and sample size simulations.

Main Results:

• Among 354 individuals with RIS, 13.8% experienced a clinical event within 2 years, with an estimated conversion risk of 19.2%.
• Key predictors for earlier conversion included younger age (<37 years), spinal cord lesions, and gadolinium-enhancing lesions on the index MRI scan.
• Individuals with three risk factors faced a significantly higher risk (90.9%) of conversion within 2 years compared to those with none.

Conclusions:

• Age under 37, spinal cord lesions, and enhancing MRI lesions are significant predictors of earlier clinical MS onset in RIS patients.
• These identified risk factors are crucial for patient stratification and optimizing clinical trial design.
• The findings aid in determining the necessary sample size for future therapeutic trials in RIS.