Modelling Disease Progression of Multiple Sclerosis in a South Wales Cohort

Abstract

<b><i>Objectives:</i></b> The objective of this study was to model multiple sclerosis (MS) disease progression and compare disease trajectories by sex, age of onset, and year of diagnosis. <b><i>Study Design and Setting:</i></b> Longitudinal EDSS scores (20,854 observations) were collected for 1,787 relapse-onset MS patients at MS clinics in South Wales and modelled using a multilevel model (MLM). The MLM adjusted for covariates (sex, age of onset, year of diagnosis, and disease-modifying treatments), and included interactions between baseline covariates and time variables. <b><i>Results:</i></b> The optimal model was truncated at 30 years after disease onset and excluded EDSS recorded within 3 months of relapse. As expected, older age of onset was associated with faster disease progression at 15 years (effect size (ES): 0.75; CI: 0.63, 0.86; <i>p</i>: &lt;0.001) and female-sex progressed more slowly at 15 years (ES: −0.43; CI: −0.68, −0.18; <i>p</i>: &lt;0.001). Patients diagnosed more recently (defined as 2007–2011 and &gt;2011) progressed more slowly than those diagnosed historically (&lt;2006); (ES: −0.46; CI: −0.75, −0.16; <i>p</i>: 0.006) and (ES: −0.95; CI: −1.20, −0.70; <i>p</i>: &lt;0.001), respectively. <b><i>Conclusion:</i></b> We present a novel model of MS outcomes, accounting for the non-linear trajectory of MS and effects of baseline covariates, validating well-known risk factors (sex and age of onset) associated with disease progression. Also, patients diagnosed more recently progressed more slowly than those diagnosed historically.