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Effect of disease modifying therapies on long-term multiple sclerosis disability and mortality
I. Poliakov, L.M. Metz Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
Aim: Determine the association between disease modifying therapy (DMT) and mortality, as well as long term disability, as measured by the expanded disability status scale (EDSS), in relapsing-remitting multiple sclerosis (MS).
Background: While the beneficial effect of DMT on MS relapse rates and magnetic resonance imaging (MRI) lesion load is well established, the effect on long term disease progression and disability is less clear. Given the slow rate at which disability accumulates, prolonged gold standard randomized clinical trials for late stage changes are burdensome, and often unfeasible. Hence, observational studies have been used to determine whether DMT influences long term disability. Controversy still exists, as results are mixed - although most studies have shown some benefit.
Methods: Analysis of EDSS and DMT data in the Calgary MS database, from consenting Calgary MS clinic patients. Patients were included if they were initially seen after January 1, 1996; had at least 5 years follow up; initially diagnosed with relapsing-remitting MS; and had an initial EDSS < 7. A comparison of final EDSS scores, disability outcomes and mortality was done between patients with at least 5 year cumulative DMT exposure and those with less than 5 years exposure (many of whom had no exposure). These groups were labeled DMT and non-DMT, respectively.
Results: 1543 patients were included for analysis; 954 in the DMT group and 589 in the non-DMT group. Mean follow up was 12.03 years (range: 5.03 to 19.72). Initial EDSS scores were not statistically different between the DMT and non-DMT groups (2.21 vs. 2.28). Average cumulative time on therapy was much higher in the DMT group, compared to the non-DMT group (11.18 years vs. 1.17 years). Patients in the DMT group had lower final EDSS scores (3.17 vs. 3.62), lower EDSS change per year (0.073 vs. 0.116), and a lower percentage of patients with EDSS >= 3 (odds ratio (95% CI): 0.77 (0.62-0.94)), EDSS >= 6 (odds ratio (95% CI): 0.65 (0.52-0.83)), or deceased (odds ratio (95% CI): 0.55 (0.33-0.91)). Results were all statistically significant in univariate and multivariate analyses.
Conclusion: This study suggests that prolonged use of DMT in the treatment of MS is correlated with decreased disability and decreased mortality, after more than a decade of follow up.
I. Poliakov, L.M. Metz Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
Aim: Determine the association between disease modifying therapy (DMT) and mortality, as well as long term disability, as measured by the expanded disability status scale (EDSS), in relapsing-remitting multiple sclerosis (MS).
Background: While the beneficial effect of DMT on MS relapse rates and magnetic resonance imaging (MRI) lesion load is well established, the effect on long term disease progression and disability is less clear. Given the slow rate at which disability accumulates, prolonged gold standard randomized clinical trials for late stage changes are burdensome, and often unfeasible. Hence, observational studies have been used to determine whether DMT influences long term disability. Controversy still exists, as results are mixed - although most studies have shown some benefit.
Methods: Analysis of EDSS and DMT data in the Calgary MS database, from consenting Calgary MS clinic patients. Patients were included if they were initially seen after January 1, 1996; had at least 5 years follow up; initially diagnosed with relapsing-remitting MS; and had an initial EDSS < 7. A comparison of final EDSS scores, disability outcomes and mortality was done between patients with at least 5 year cumulative DMT exposure and those with less than 5 years exposure (many of whom had no exposure). These groups were labeled DMT and non-DMT, respectively.
Results: 1543 patients were included for analysis; 954 in the DMT group and 589 in the non-DMT group. Mean follow up was 12.03 years (range: 5.03 to 19.72). Initial EDSS scores were not statistically different between the DMT and non-DMT groups (2.21 vs. 2.28). Average cumulative time on therapy was much higher in the DMT group, compared to the non-DMT group (11.18 years vs. 1.17 years). Patients in the DMT group had lower final EDSS scores (3.17 vs. 3.62), lower EDSS change per year (0.073 vs. 0.116), and a lower percentage of patients with EDSS >= 3 (odds ratio (95% CI): 0.77 (0.62-0.94)), EDSS >= 6 (odds ratio (95% CI): 0.65 (0.52-0.83)), or deceased (odds ratio (95% CI): 0.55 (0.33-0.91)). Results were all statistically significant in univariate and multivariate analyses.
Conclusion: This study suggests that prolonged use of DMT in the treatment of MS is correlated with decreased disability and decreased mortality, after more than a decade of follow up.