Prevalence and Characteristics of Restless Leg Syndrome in Thai Patients With Parkinson's Disease

In the general population, the prevalence of RLS was reported to be up to 10%. In Parkinson's disease (PD), the mean prevalence of RLS was 15.74%. Cross-sectional studies show a variable prevalence of RLS in PD patients ranging approximately from 0 to 50%. In case-control studies, the mean prevalence of RLS was higher in people with PD (12%) vs. healthy controls (5.1%). One four-year longitudinal study reported an increase in RLS prevalence from 4.6% to 16.3% along with disease progression. Interestingly, RLS was found to have various prevalence depending on geographic areas: highest in European populations (5% to 12%), intermediate in Asian countries (1% to 8%), and lowest in African countries (\<1%). In Patients with Parkinson's disease, diagnosis of RLS is challenging due to multiple confounders such as motor fluctuations, akathisia, etc. It is crucial to pick up RLS in Parkinson's disease and properly manage the symptoms. RLS not only causes impaired quality of life but also possibly leads to cardiovascular consequences. RLS was associated with statistically significantly less future cardiovascular risk in RLS patients with treatment than in those without treatment. Nevertheless, there have been no consistent studies of this association in Parkinson's disease yet. From the literature review, very few data have been stated regarding RLS in Thai patients with Parkinson's disease. There was only one study focusing on the prevalence of RLS in Thailand, in which the prevalence of RLS in Thai Parkinson's patients was only 1.6%. According to the author, there were possible explanations for the low prevalence. Firstly, they only included participants with idiopathic RLS. Secondly, high doses of dopaminergic agents might obscure the symptoms of RLS in those patients with Parkinson's disease. Moreover, they screened patients with the Cambridge-Hopkins diagnostic questionnaire which had not been validated in Thai people yet. For all these reasons, we believe that the prevalence of RLS in Thai patients with Parkinson's disease would be different with another methodology. We also would like to know more about the characteristics of RLS in Thai Parkinson's disease patients, which might help improve RLS detection in this population.