Sleep disorders among dementia patients and their related factors

Dementia and sleep disorders have bidirectional effects. The association between sleep and the risk of dementia is well known. Sleep disorders and sleep-related problems are common among dementia patients. Older adults are more likely to have lower sleep efficiency and a higher prevalence of sleep disorders. In this study, the authors investigated sleep disorders and related factors among dementia patients. The National Health Insurance Service-Elderly Cohort Database, acquired from the Korean National Health Insurance Service (NHIS) for the years 2002 to 2019, was used. To investigate the factors associated with sleep disorders, dementia patients with accompanying sleep disorders were identified. Age, sex, the number of days spent in hospitals or nursing care facilities, and the prevalence of hypertension, diabetes, cancer, and disability were compared between dementia patients with and without sleep disorders. A total of 180,536 participants were diagnosed with dementia, and 61,058 (33.8%) had accompanying sleep disorders. The prevalence of these sleep disorders did not significantly differ by sex among dementia patients. Dementia patients without sleep disorders were significantly older than those with sleep disorders (p < 0.001). The proportion of patients with disabilities was greater in the group with sleep disorders (29.7%) than in the group without sleep disorders (28.8%). The number of days spent in hospitals or nursing care facilities did not significantly differ between the two groups (p = 0.818). The prevalence of hypertension, diabetes, and cancer was also higher in the group with sleep disorders than in the group without sleep disorders (all p < 0.001). Compared with dementia patients with sleep disorders, those without sleep disorders had higher scores in physical function, cognitive function, behavioural changes, and rehabilitation, indicating worse health status. However, in the nursing intervention score area, dementia patients with sleep disorders had higher scores than those without sleep disorders, suggesting that patients with sleep disorders require more nursing interventions (p < 0.001). Age, hypertension, diabetes, and cancer were significantly associated with the risk of sleep disorders among dementia patients. Sleep disorders are common symptoms among dementia patients, and their risk varies depending on their characteristics. Additionally, the presence or absence of sleep disorders can affect patients’ need for long-term care, so sleep disorders in dementia patients should be treated appropriately.