Sleep microstructure and clinical characteristics of patients with restless legs syndrome

Study objectives: Restless legs syndrome (RLS) is a sleep-related movement disorder, often accompanied by sleep disruption. Obstructive sleep apnea (OSA) has a controversial prevalence among patients with RLS. We evaluated the clinical and sleep features of patients who attended our sleep clinic considering RLS and OSA.

Methods: In this cross-sectional study, we obtained health records of 1,497 patients during 2015-2019 who underwent polysomnography (PSG). Baseline characteristics, sleep-related and RLS questionnaires, and sleep microstructure were assessed. Descriptive and analytical assessments were performed. RLS was assessed according to the International Restless Legs Syndrome Study Group criteria.

Results: RLS was found in 19.4% of patients, with more prevalence among women (26.9% vs 16.4%). RLS affected 19.1% of patients with OSA. Patients with RLS were significantly older with higher insomnia and depression and worse PSG results. As the respiratory disturbance index increased, the odds of RLS slightly decreased (adjusted odds ratio [95% confidence interval]: 0.80 [0.67-0.94]). The odds of OSA (respiratory disturbance index ≥ 5) was not affected by RLS. OSA in patients with RLS was significantly associated with a higher limb movement index. RLS in patients with OSA was significantly associated with higher insomnia, depression, and limb movement index (men and women), higher wake after sleep onset and percentage of N1 sleep (men), and lower sleep efficiency (men).

Conclusions: Patients with RLS had worse PSG results, higher insomnia, and depression. Although men with OSA+/RLS+ had worsened PSG results, PSG parameters in women with OSA+/RLS+ did not differ from the OSA+/RLS- group. Patients with either OSA or RLS should be evaluated for possible comorbidities, including insomnia and depression. Notably, sex-specific characteristics need more consideration in sleep clinics.

Citation: Amirifard H, Jameie M, Akbarpour S, et al. Sleep microstructure and clinical characteristics of patients with restless legs syndrome. J Clin Sleep Med. 2022;18(11):2653-2661.