T2 lesions and rate of progression of disability in multiple sclerosis

Background and purpose: To assess the predictive value of T2 lesions on the rate of progression of disability in multiple sclerosis (MS). Methods: We reanalyzed T2 lesion number and load on brain MRI scans, performed before 1997, of 186 MS patients, who were clinically followed. There were 90 patients with progressive MS (35 secondary progressive and 55 primary progressive), and 96 with relapsing remitting MS. The rate of progression of disability was measured by time to sustained progression of disability (defined as an increase in >= 1 point when the Expanded Disability Status Scale (EDSS) was 5.5 or less and an increase in EDSS of >= 0.5 point when the EDSS was 6.0 or higher), and by the Multiple Sclerosis Severity Score (MSSS). Results: During follow-up (median 15 years, IQR 12-17 years), 94% of the patients with progressive MS and 50% of the patients with relapsing remitting MS had progression of disability. Higher T2 lesion number and load were modestly associated with a higher rate of disease progression on the MSSS and a shorter time to progression of disability in relapsing remitting MS, but not in progressive MS. Conclusions: Our findings indicate that the amount of T2 lesions has a small predictive value for progression of disability in relapsing remitting MS, but has no influence on the rate of progression in progressive MS.