Prevalence of restless legs syndrome in patients with multiple sclerosis, as confirmed by sleep disorders specialists

Depending on the methodology used, the prevalence of restless legs syndrome (RLS) in people with multiple sclerosis (PwMS) ranges from 13 to 65%. This study aimed to evaluate the prevalence of RLS in PwMS using a case-control design, with each case confirmed by a sleep disorder specialist.

Prevalence of RLS was analyzed in a hospital cohort of 440 PwMS and 241 age- and sex-matched control subjects. Cases were identified through two interviews. First, participants answered to a structured questionnaire, and second, those who met the criteria for any cardinal RLS symptoms were interviewed by a sleep disorder specialist to confirm the diagnosis. Multivariate regression was used to analyze the clinical and radiological characteristics of MS associated with RLS.

Of the 86 PwMS who tested positive for RLS using the questionnaire, 67 were diagnosed by a sleep specialist, corresponding to a prevalence of 15.23% (95% CI 11.80-19.34) compared to 19.55% (95% CI 15.63-24.14) based solely on the questionnaire (false positive: 22.09%). PwMS were twice as likely to suffer from this syndrome as the control group (OR 2.148, 95% CI 1.218-3.788, p = 0.008). Family history of RLS (OR 5.291, 95% CI 2.407-11.629, p < 0.0001) and pyramidal tract involvement (OR 4.208 95% CI 1.940-9.128, p < 0.0001) were the only factors associated with RLS.

PwMS are twice as likely to develop RLS as the general population. Pyramidal tract involvement appears to be a risk factor for developing RLS in this disease.