Restless legs syndrome in multiple sclerosis patients: Prevalence, impact, and association with disease-modifying therapies in a Saudi Arabian pilot study

Background: Restless legs syndrome (RLS) emerges as a notable sleep disorder characterized by distressing sensations within the lower extremities. Its prevalence appears to be higher among patients afflicted with multiple sclerosis (MS) compared to the general population. Despite this observation, the understanding of the intricacies of RLS and its repercussions within the context of MS patients in Saudi Arabia remains limited. Methods: Employing a cross-sectional design, a comprehensive investigation was undertaken at King Fahad Armed Forces Hospital in Jeddah, Saudi Arabia, spanning from November 2021 to March 2022. A cohort of 66 individuals diagnosed with MS was recruited and subjected to an assessment for RLS employing the revised diagnostic criteria outlined by the International Restless Legs Syndrome Study Group (IRLSSG). Furthermore, the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Sleepiness Scale were employed to gage the extent of RLS's impact on sleep quality and daily functioning. Results: The prevalence of RLS amidst the MS cohort was determined to be 30.4%. An observable association was discerned between RLS presence and higher scores on the Expanded Disability Status Scale (p < 0.001), along with diminished sleep quality scores (p < 0.001) and elevated fatigue scores based on IRLSSG criteria (p < 0.001). Within the studied MS cases, 98.5 % exhibited the relapsing-remitting subtype. Further investigation demonstrated that patients treated with Fingolimod or Ocrevus presented normal IRLSSG scores, whereas those undergoing Rituximab treatment manifested an even distribution between normal and moderate scores. Correspondingly, patients receiving interferons showcased 72.2 % with normal scores and 27.8 % with mild scores. Notably, a statistically significant variance in IRLSSG scores was observed when contrasting Fingolimod and Aubagio treatments (P < 0.001). Conclusion: The presence of RLS as a comorbidity in MS patients within the Saudi Arabian context emerges as a significant finding, exerting a discernible detrimental influence on both disability status and sleep quality. This study underscores the need for further investigations aimed at unraveling the intricate pathophysiological underpinnings, identification of risk factors, and exploration of therapeutic modalities for RLS in this population. Furthermore, additional research endeavors are warranted to elucidate the diverse impact of various disease-modifying therapies on clinical outcomes.