Loren A. Rolak, Brent Olson and Po-Huang ChyoU
Background: Although many studies have shown shortterm benefits of disease modifying drugs (DMDs) in reducing relapse rates in patients with multiple sclerosis (MS), the data about long-term effects is more scarce and less certain. The objective of this study was to determine the natural history of relapsing-remitting multiple sclerosis, both treated and untreated, in a real-world setting.
Methods: We analyzed relapse rates and disability scores in 891 patients in a specialized MS clinic followed in a longitudinal database for as long as 21 years. We compared 370 patients who never received treatment with 521 who had prolonged therapy with one of the various DMDs.
Findings: Most patients with relapsing-remitting disease did well, and accumulation of disability was slow regardless of treatment. Among patients followed 10 years or more, mean [median]Expanded Disability Status Scale scores were 3.0 [2.0] among untreated patients and 4.2 [4.3] among treated patients (p=0.0032).There was no correlation between number of relapses and disability.
Conclusion: Many patients have a mild course and accumulate little or no disability. Patients with more severe disease continue to worsen despite therapy but often still do well.