Abnormalities on structural MRI associate with faster disease progression in multiple system atrophy

Abstract

Background: The rate of clinical progression in patients with multiple system atrophy (MSA) varies between individuals and predictors for disease progression remain undefined. While the MSA-rasagiline study found no difference in the rates of clinical progression for patients treated with rasagiline versus placebo, it included a large, prospective magnetic resonance imaging (MRI) substudy that can provide new information on the underlying disease progression in patients with early MSA.

Methods: This post-hoc analysis compared the rate of clinical progression in patients with MSA-specific structural changes at baseline (MRI-positive group) versus the rate of progression in patients without evidence of such changes at baseline (MRI-negative group) using a repeated measures ANCOVA. Clinical progression was assessed using the Unified MSA Rating Scale (UMSARS) and Clinical Global Impression of Improvement (CGI-I).

Results: Twenty-eight patients with early MSA of the parkinsonian subtype (MRI-positive n = 13; MRI-negative n = 15) who had complete baseline and follow-up UMSARS data were included in this analysis. Patients in the MRI-positive group had faster clinical progression from baseline to the end of the 48-week study compared with those in the MR-negative group as assessed by the UMSARS total (p = 0.028) and UMSARS motor (p = 0.008) scales. At week 48, MRI-positive patients also had a significantly worse health status vs. MRI-negative patients (p = 0.015).

Conclusions: This is the first study to demonstrate that MSA-specific abnormalities on structural MRI might represent a variant of MSA-P that is associated with more rapid progression and an overall worse prognosis.

Keywords: Biomarker; Magnetic resonance imaging; Multiple system atrophy; Rasagiline.