Long-term correlation found between T2 lesions and disability in MS

Researchers have found a strong long-term correlation between T2 brain lesions and disability in relapsing-remitting Multiple Sclerosis (MS) with age significantly impacting the clinical correlation. MRI monitoring for the presence of brain lesions in patients is used as an outcome measure in almost all MS clinical trials. Prior studies that have investigated the relationship between T2 lesions and disability have found limited correlation, which has led to what is known as the "MRI-clinical disconnect". Authors Rudick et al. suggest that T2 lesions may be strongly predictive of future disease severity if assessed as part of long-term follow-up studies, which to date, have not been conducted. In order to determine the relationship between lesions visible on T2-weighted MRI scans during the relapsing-remitting phase of MS and future disease severity, the authors performed standardised follow-up examinations in a group of patients who were entered into a clinical trial for relapsing-remitting MS over a 13-year period.A total of 30 patients from a total of 301 patients who entered a randomised, double-blinded, placebo-controlled, phase III trial of interferon-Β-1a in 1990 were included in the current study. Outcomes to assess disease severity at baseline and last visit included the Expanded Disability Status Scale (EDSS), MS Functional Composite (MSFC) and its components, and brain parenchymal fraction (BPF). Baseline MRI lesions and their change over 2 years were tested for correlation with EDSS, MSFC, BPF, lesion Magnetisation Transfer Ratio (MTR) and Normal Appearing Brain Tissue (NABT) MTR at the last visit.The results revealed that baseline T2 lesions volume correlated with the BPF of the last visit (r = -0.66; pThe authors note that the effect of age on the relation between T2 lesions and clinical outcome suggests that "age is a significant factor in determining whether an MS patient with a given amount of disease pathology will have exceeded the threshold required to manifest clinical disability." They go on to recommend that age be considered as a significant covariate in population studies and clinical trials evaluating the impact of prognostic factors and disease-modifying therapies.They concluded, "the results provide direct evidence for the disability threshold hypothesis in MS and support monitoring T2 lesions in relapsing-remitting MS."Reference...