Subgroups of multiple sclerosis patients with larger treatment benefits: a meta-analysis of randomized trials

Abstract

Background and purpose: No subgroups of patients with higher treatment effects have been clearly detected in multiple sclerosis (MS). The aim of the present work was to evaluate whether there are subgroups of relapsing-remitting MS (RRMS) patients who are more responsive to treatments.

Methods: All published randomized clinical trials in RRMS reporting a subgroup analysis of treatment effect were collected. Two main outcomes, the annualized relapse rate (ARR) and the disability progression, were studied. The treatment effect in each subgroup was reported as a relative effect (RE), defined as the treatment effect in the subgroup relative to the overall effect. A meta-analysis was run to compare the RE between subgroups.

Results: Six trials (6693 RRMS patients) were included. Treatment effects on ARR were significantly higher in younger than in older subjects (RE = 0.83 vs. RE = 1.30, P < 0.001), in patients with than those without gadolinium activity (RE = 0.86 vs. RE = 1.15, P = 0.005) and in patients with lower than in those with higher Expanded Disability Status Scale (RE = 0.96 vs. RE = 1.23, P = 0.02), and on disability progression in younger than in older subjects (RE = 0.82 vs. RE = 1.28, P = 0.017).

Conclusions: This study formally shows that in RRMS higher treatment effects are associated with characteristics of earlier (lower age and Expanded Disability Status Scale) and more active (higher gadolinium activity) disease.

Keywords: disability progression; early treatment; larger treatment effect; meta-analysis; randomized controlled clinical trials; relapse rate; subgroup analysis.