Mortality in patients with behavioural and psychological symptoms of dementia: a registry-based study

Objectives: Behavioural and psychological symptoms of dementia (BPSD) are common in patients with dementia. In the elderly population, comorbidities frequently coexist with dementia and mortality in dementia is high. The aim of this study was to investigate the impact of BPSD on mortality in severe dementia. Methods: This study of 11,448 individuals was based on linked information from the Swedish BPSD registry, the National Patient Register and the Cause of Death register. BPSD was assessed with the Neuropsychiatric Inventory (NPI). Cox proportional hazards regressions were performed for survival analysis. To study different degrees of BPSD, data was categorized into groups: no (NPI, 0 points), mild (NPI, 1-3 points on >= 1 item), moderate (NPI, 4-8 points on >= 1 item) and severe (NPI, 9-12 points on >= 1 item) BPSD based on the highest score on any of the BPSD assessed (NPI items). Results: The presence of moderate or severe BPSD was associated with a stepwise increased risk of mortality (hazard ratio (HR), 1.31; 95% confidence interval (CI), 1.08-1.60 and HR 1.74; 95% CI 1.44-2.12, respectively) compared with individuals with no BPSD. In addition, there was an association between total NPI score and mortality (HR 1.01; 95% CI 1.007-1.010). The results remained significant after multivariable adjustment for age, sex, dementia diagnosis, medication, previous myocardial infarction, hip fracture and stroke. Conclusions: The results show a stepwise increase in mortality risk with increased BPSD, highlighting the importance of adequate management of BPSD to reduce mortality in dementia.