Restless Legs Syndrome in Multiple Sclerosis: Risk factors and effect on sleep quality - a case-control study.

INTRODUCTION Previous studies suggested an association between MS and Restless Legs Syndrome (RLS). Data on the prevalence of RLS in Austrian MS patients and on the influence of disease-modifying therapies (DMT) on RLS are lacking. OBJECTIVE To investigate (1) the prevalence of RLS in Austria compared to control persons (CP), (2) risk factors for RLS in MS, and (3) influence of DMTs on RLS prevalence and/or severity. METHODS Adult MS patients and CP were screened for RLS by face-to-face interviews, including questionnaires for RLS severity, sleep quality and daytime sleepiness. RESULTS 23.9% of MS patients (n=117) had RLS compared to 3.4% (p<0.001) of CP (n=119). The MS+RLS group (n=28) had a higher rate of sleep impairment (78.6% vs 21.3%, p<0.001) and excessive daytime sleepiness (32.1% vs 15.7%, p=0.045) compared to the MS-RLS group. Multivariate regression analysis revealed higher Expanded Disability Status Scale and spinal lesions in MRI as risk factors for RLS in MS, while DMTs had no impact on RLS. CONCLUSION Roughly a quarter of MS patients suffers from RLS, significantly impacting quality of life by poor sleep quality and excessive daytime sleepiness. RLS risk increases with physical disability and spinal lesions but is independent of DMT.