The relationship between the rate of brain volume loss during first 24 months and disability progression over 24 and 48 months in relapsing MS

Clinical evidence in patients with relapsing-remitting multiple sclerosis suggests an association between MRI outcome measures and disability progression (DP). Post hoc analysis to investigate the association and potential predictive value of brain volume loss (BVL) with long-term DP in FREEDOMS. Patients were categorized into quartiles by SIENA-calculated percent brain volume change from baseline to month (M) 24. Patient characteristics at baseline were determined for each quartile, as were the proportions of patients at M24 and M48 reaching Expanded Disability Status Scale (EDSS) scores of ≥4.0 or ≥6.0 or DP confirmed at 3 months (CDP3) or 6 months (CDP6), and change in EDSS and Multiple Sclerosis Functional Composite. MS disease activity and severity as well as brain volume at baseline were predictive of subsequent BVL over 24 months. The quartiles of patients with greater BVL at 24 months were at highest risk (odds ratio, p value) for reaching EDSS ≥4 (2.8, p = 0.001) or ≥6 (5.73, p = 0.0005) and experienced more DP at M24 (CDP3 2.13, p = 0.002; CDP6 2.17, p = 0.003) and M48 (CDP3 1.98, p = 0.006; CDP6 1.87, p = 0.018) compared to the quartile of patients with the least amount of BVL. These findings confirm the clinical relevance of early brain volume changes for long-term DP.