Prevalence of behavioural and psychological symptoms of dementia in cognitively impaired elderly residents of long-term care facilities in East Asia: a cross-sectional study

Objective The aim of this study was to compare the prevalence of behavioural and psychological symptoms of dementia (BPSD) in cognitively impaired elderly residents of long-term care facilities in East Asia and to explore the factors associated with these patterns. Methods This was a cross-sectional survey of BPSD in cognitively impaired elderly residents of long-term care facilities in Japan, South Korea, China, Taiwan, and Thailand. The Mini-Mental State Examination, Clinical Dementia Rating (CDR), and Neuropsychiatric Inventory, Nursing Home version (NPI-NH), were used to assess cognitive status, dementia severity, and BPSD, respectively. NPI-NH subscale severity scores were multiplied by frequency scores to obtain the subscale scores and aggregated into two groups based on score (clinically insignificant = 1- 3; clinically significant >= 4). Results Data from 662 people were analyzed. Median age, median Mini-Mental State Examination scores, and median CDR scores differed significantly among the seven study sites. The prevalence of BPSD varied from 64% in Taiwan to 100% in dementia care units in Japan, and the median total NPI-NH scores ranged from 2 in Taiwan to 14 in dementia care units in Japan. After stratification of the sample by dementia severity and clinical significance of NPI-NH scores, differences in the prevalence of clinically significant BPSD were mostly observed among facilities dedicated to dementia patients in the CDR 1 group. In the CDR 3 group, the prevalence of some clinically significant BPSD, such as apathy, was high even among study sites with low median total NPI-NH scores. Conclusions Our findings may suggest referral and selection biases in the study sites. Future prospective studies are needed to address the impact of environmental and care factors on the occurrence of BPSD in Asian countries.