Restless Legs Syndrome and fatigue in multiple sclerosis: A cross-sectional clinical study

Restless Legs Syndrome is a sleep-related sensorimotor disorder with a higher prevalence in Multiple Sclerosis (MS) patients than in the general population. Our aim was to determine the prevalence of RLS in a group of relapsing-remittent multiple sclerosis (RRMS) patients, and to investigate whether RLS is associated with MS-related disability, sleep quality, mood disorders and fatigue.

In this retrospective, mono-centric, observational study, 92 RRMS patients were recruited (median age 46.5 years, 68.5% female patients). Data on MS clinical and radiological variables were collected. Patients underwent a subjective evaluation with standardized questionnaires on sleep fatigue and mood, which were evaluated by an expert neurologists specialized in sleep disorders about the occurrence of RLS.

Prevalence of RLS in our sample was of 47.8%. Patients with RLS had a significantly higher rate of worse sleep quality and fatigue, compared to non RLS subjects (respectively 56.8% vs. 35.4%, p=0.04 and 54.4% vs 22.7%, p=0.002). Univariate analysis showed that RLS was significantly more frequent in fatigued patients (66.7% vs 38.5% RLS- patients, p=0.009). Multivariate analysis showed that fatigue correlated with MS-related disability (OR 1.556, p=0.011), poor sleep quality (OR 1.192, p 0.036), and mood disorders (OR 1.096, p 0.046). RLS appears to independently increase the risk of fatigue of 50%, without reaching clear statistical significance (OR 1.572, p 0,0079).

Our study confirms the high prevalence of RLS in patients with multiple sclerosis and highlights the potential impact of RLS on fatigue and its strict interaction with sleep quality.