The use of valproic acid and multiple sclerosis

Area of Science:

• Neuroscience
• Pharmacology
• Epidemiology

Background:

• Animal studies suggest histone deacetylase inhibitors may benefit multiple sclerosis (MS).
• Valproic acid (VPA) is an anti-epileptic drug with histone deacetylase inhibitory properties, making it a candidate for MS treatment investigation.

Purpose of the Study:

• To investigate the association between valproic acid (VPA) use and the risk of developing multiple sclerosis (MS).

Main Methods:

• A propensity score-matched cohort study was conducted using nationwide register data from 1997-2011.
• VPA users were matched 1:4 with non-users based on propensity scores.
• Cox regression analysis was used to compare MS incidence rates and estimate hazard ratios (HRs).

Main Results:

• The study included 16,028 VPA ever-users and 54,172 non-users, with 18 and 26 MS cases identified, respectively.
• Neither current nor recent VPA users showed a reduced risk of MS compared to non-users (HRs ranging from 1.22 to 1.30).
• An intention-to-treat analysis also found no reduced risk of MS for VPA ever-users (HR = 2.41).

Conclusions:

• The first human study on VPA and MS risk found no evidence of a protective effect.
• While no protective effect was observed, wide confidence intervals mean only large effects can be definitively ruled out.