Behavioral and psychological symptoms of dementia and mortality risk among people with cognitive impairment: an 8-year longitudinal study from the NCGG-STORIES

Background: Behavioral and psychological symptoms of dementia (BPSD) are common among people with dementia from the early stages and can appear even in mild cognitive impairment (MCI). However, the prognostic impact of BPSD is unclear. This study examined the association between BPSD and mortality among people with cognitive impairment.

Methods: This longitudinal study involved 1,065 males and 1,681 females (mean age: males = 77.1 years; females = 78.6 years) with MCI or dementia diagnosis, from the National Center for Geriatrics and Gerontology-Life Stories of People with Dementia (NCGG-STORIES), a single-center memory clinic-based cohort study in Japan that registered first-time outpatients from 2010–2018. Information about death was collected through a mail survey returned by participants or their close relatives, with an up to 8-year follow-up. BPSD was assessed using the Dementia Behavior Disturbance Scale (DBD) at baseline.

Results: During the follow-up period, 229 (28.1%) male and 254 (15.1%) female deaths occurred. Cox proportional hazards regression analysis showed that higher DBD scores were significantly associated with increased mortality risk among males, but not females (compared with the lowest quartile score group, hazard ratios [95% confidence intervals] for the highest quartile score group = 1.59 [1.11–2.29] for males and 1.06 [0.66–1.70] for females). Among the DBD items, lack of interest in daily living, excessive daytime sleep, and refusal to receive care had a higher mortality risk.

Conclusions: The findings suggest a potential association between BPSD and poor prognosis among males with cognitive impairment.