Lewis RA, McDermott MP, Herrmann DN, et al., JAMA Neurol 2013;70:981-987.
Submitted by Andrew Tarulli, MD, NSE Board
Results of a Randomized, Double-Masked, Controlled Trial
The Muscle Study Group performed a randomized controlled trial to determine whether high-dose (4 g/d) ascorbic acid (AA) improved neuropathy in patients with Charcot-Marie-Tooth disease type 1A (CMT1A). 110 patients with CMT1A diagnosed a mean of 14 years prior to enrollment were allocated in a 4:1 ratio to the AA and placebo group, respectively. The mean CMT Neuropathy Score (CMTNS) at baseline was 16.5 (4.5). Over two years, the mean change in the CMTNS was -0.21 for the AA group and -0.92 for the placebo group, a non-significant difference. Both groups compared favorably to historical controls. The investigators concluded that although the results did not reach futility, it was unlikely that a dose of AA 4 g/d produced a clinically meaningful effect on the course of CMT1A.
This is one of the largest randomized controlled trials of an intervention for patients with CMT. Earlier studies using lower doses of AA did not prove effective, but higher doses in mouse models improved both clinical and histological outcomes. Although high-dose vitamin C did not appear to provide a meaningful benefit for patients with CMT1A, it is possible that patients were treated too late in their courses (mean of 14 years after diagnosis), after irreversible progression had already occurred.
About the News Science Editorial Board
The AANEM News Science Editorial (NSE) Board
compiles quarterly summaries of signficant research from journals and websites publishing neuromuscular and electrodiagnostic medicine research.