Restless legs syndrome in patients with Parkinson's disease: a comparative study on prevalence, clinical characteristics, quality of life and nutritional status

Background Restless legs syndrome (RLS) is a common neurological disorder that can coexist with Parkinson's disease (PD). However, the association between these two movement disorders is quite poorly explored and previous findings are controversial in different aspects. Objective To compare prevalence of RLS in Iranian PD population with a matched control group and to investigate the impact of comorbid RLS on quality of life (QoL), nutritional status, and clinical characteristics in PD population. Methods This study was conducted on 108 individuals with idiopathic PD (IPD) and 424 matched controls. RLS was diagnosed using the International Restless Legs Syndrome Study Group (IRLSSG) criteria. Further assessments were performed on clinical characteristics, PD severity scales, psychiatric features, nutritional status, fatigue, and QoL in PD patients with and without RLS. Results Restless legs syndrome was significantly more common among the patients with IPD (14.8%) compared to the controls (7.5%) [OR = 2.1 (95% CI: 1.1–4.0)]. IPD subjects with RLS had significantly higher anxiety score [10.1 (SD = 5.1) vs 5.9 (SD = 5.0); P = 0.003], worse nutritional status [23.7 (SD = 2.7) vs 25.4 (SD = 3.7); P = 0.008], and poorer QoL [26.9 (SD = 13.1) vs 17.0 (SD = 13.2); P = 0.006]. The number of positive answers to the IRLSSG diagnostic criteria had significant direct correlation with unpredictability of the off periods and the presence of symptomatic orthostasis. Conclusions Our study demonstrated a higher prevalence of RLS in patients with PD compared to general population. PD patients with RLS suffer from more anxiety, worse nutritional status, and worse QoL. RLS negatively accompanies with psychiatric problems, emotional behaviors, stigma, and cognitive impairment.