Abstract
Objectives: Periodic limb movements of sleep (PLMS) is known to accompany restless legs syndrome, and studies on PLMS are limited. Moreover, the relationship between insomnia and PLMS is underrecognized. This study aimed to investigate the polysomnography (PSG) data, questionnaires, and iron-related laboratory data of patients with insomnia and were confirmed PLMS.Methods: Between April 2015 and May 2022, 423 patients with insomnia as the primary symptom who were diagnosed with PLMS based on overnight PSG were included and divided into three groups based on their PLM index (PLMI). The participants’ demographics, insomnia-related questionnaires, PSG findings, and iron-related laboratory findings were used in the analysis.Results: The severe PLMS group (PLMI >50) were mostly males, had more individuals taking sleeping pills, and had higher body mass index than the mild PLMS group (PLMI 5–25). Significant differences were not found in questionnaire about insomnia and sleep quality. In PSG, the severe PLMS group showed shorter total sleep time and low spontaneous arousal index than the mild to moderate PLMS groups. Moreover, more patients in the severe PLMS group showed arrhythmia than the mild PLMS group. Ferritin and transferrin saturation results had no significant difference between the three groups.Conclusions: PLMS did not affect the severity of insomnia and fatigue. The results shown in PSG may be influenced by age or sleeping pills intake. Arrhythmia was higher in the severe PLMS group. More studies on the causal relationship between PLM and cardiac diseases are needed.