Hughes J, et al. - Via this observational cohort study from MSBase (a prospectively collected, international database) researchers investigated the role of inflammatory relapses in disability accumulation for patients with progressive-onset multiple sclerosis (MS). Findings revealed a lower risk of confirmed disability progression in association with superimposed relapses in progressive-onset MS. This seemed to be related to disease-modifying therapy’s association with the prevention of relapse-related disability accrual in patients with superimposed relapse. Findings thereby highlight that in progressive-onset disease, inflammatory relapses are an important and modifiable determinant of disability accrual.

Methods

• From January 1995 to February 2017, researchers collected the data.
• In February 2017, data analyses began.
• They identified 44,449 patients at time of extraction; of these, 1,419 were eligible (31.9%) for the analysis.
• Inclusion criteria for this analysis was primary progressive MS (PPMS) or progressive-relapsing MS (PRMS), adult-onset disease, and minimum data set (including ≥ 3 visits with disability recorded, ≥ 3 months between second and last visit).
• Multivariable regression models (Andersen-Gill) with mixed effects were used to perform data analysis.
• They performed two sensitivity analyses to exclude both relapse-related disability progression and bout-onset progressive MS.
• The patients were grouped in accordance to presence or absence of relapse; relapse is defined as an acute episode of clinical worsening.
• Cumulative hazard of disability progression was assessed as the main outcome measure.

Results

• Comparatively younger patients experienced PRMS than those experiencing PPMS (mean [SD] age, 46 [15] vs 51 [10] years, Cohen d = 0.40); PRMS patients demonstrated a mean lower Expanded Disability Status Scale score (mean [SD] score, 4.0 [3] vs 4.5 [2.5], Cohen d = 0.28) at inclusion.
• The PRMS and PPMS groups were similar regarding the men to women ratio (252:301 vs 394:472).
• Data revealed an overall mean (SD) age of 48 (11) years and 50 (10) years for men and women, respectively.
• Patients with superimposed relapses displayed lower likelihood of confirmed disability progression (hazard ratio [HR], 0.83; 95% CI, 0.74-0.94; P=.003).
• Researchers observed significantly reduced hazard of confirmed disability progression in relation to proportion of follow-up time spent on disease-modifying therapy in the cohort with relapse (HR, 0.96; 95% CI, 0.94-0.99; P=.01) but not in those without relapse (HR, 1.02; 95% CI, 0.99-1.05; P=.26).
• They did not see an association of disease-modifying therapy in the cohort with superimposed relapse when accounting for relapse-related progression (HR, 1.10; 95% CI, 0.96-1.24; P = .16).