COPENHAGEN—Time to severe disability in progressive multiple sclerosis (MS) is independently accelerated by both pre- and post-progression relapses, according to research presented at the 29th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS).
Miguel M. Paz Soldan, MD, and colleagues examined the impact of relapses—both before and after progression onset—on the tempo of post-progression disability accumulation. The researchers studied two cohorts fulfilling McDonald diagnostic criteria for MS: a population-based prevalence cohort from Olmsted County, Minnesota (n = 221), and a clinic-based progressive cohort (n = 859). Progressive disease course was classified as either primary (PPMS), secondary (SPMS), or following a single clinical attack (SAPMS). Disability was assigned per Kurtzke Expanded Disability Status Scale (EDSS). The impact of relapses was studied using a multivariate Cox regression analysis. Gender, age at progression onset, and immunomodulatory medication use were modeled as covariates. Kaplan–Meier analysis was used to generate survival curves to an EDSS score of 6.
Presence of pre-progression relapses (hazard ratio 2.20) predicted shorter time from progression onset to an EDSS score of 6. Post-progression disability accumulation was slowest in patients with PPMS (50% of patients in 10 years), followed by patients with SAPMS (50% in seven years), and fastest in patients with SPMS (50% in four years). Post-progression relapses were more common in patients with SPMS (29.5%) than in patients with SAPMS (10.7%) and patients with PPMS (3.1%), reflecting the pre-progression relapse status in these groups. Ongoing relapses after onset of progressive disease course (17.1%; hazard ratio, 1.48) independently predicted shorter time from progression onset to EDSS score of 6, which was about two years faster. Most post-progression relapses happened within five years (91.6%) after onset of progression and before age 55 (95.2%).
“Our results suggest that continuation of immunomodulation for five years after progression onset or until age 55, whichever comes first, is a reasonable approach in SPMS,” the researchers stated. “However, given the paucity of ongoing relapses, this may not be indicated in SAPMS and PPMS.”
—Glenn S. Williams
Vice President/Group Editor