A retrospective review of lithium usage in veterans with multiple sclerosis

Abstract

ObjectiveLithium (Li) reduces disease activity in animal models of multiple sclerosis (MS), but has not been previously studied in human MS. While developing a clinical trial to test the effects of Li in MS, we performed a retrospective chart review to determine the safety and tolerability of Li among US veterans with MS. MethodsWe identified all veterans with MS prescribed Li from 1998 to 2009 using the Department of Veterans Affairs Pharmacy Benefits Management. Charts were reviewed for Li-related adverse events and effects on the MS disease course. ResultsAmong 21,847 veterans with MS, 101 met inclusion criteria and took Li ≥6 months. Eighteen percent of subjects experienced a Li-associated adverse event. Later age of MS onset was associated with increased risk of Li-related adverse events (p=0.004). Associations between Li use and MS disease activity were mixed: Li was not associated with increased risk of enhancing MRI lesions (p=0.655), but annualized relapse rates were higher on Li (0.34 vs. 0.20, p=0.044). In contrast, change in Expanded Disability Status Scale scores was greater in the off-Li period than the on-Li period (0.8 vs. 0.3, p=0.003). ConclusionAdverse events occur in a minority of Li-treated MS patients. A consistent effect of Li on MS disease activity was not apparent. These findings indicate a clinical trial will be needed to ascertain Li's effects on the MS disease course.