Neuropsychiatric symptoms and mortality among patients with mild cognitive impairment and dementia due to Alzheimer's disease

Background: Neuropsychiatric symptoms (NPS) could increase mortality risk in people with dementia due to Alzheimer's disease (AD). However, whether NPS affects mortality risk in people with mild cognitive impairment (MCI) and whether any specific syndrome of NPS influences this risk are still unclear. Methods: In total, 984 participants with dementia due to AD, 338 with MCI, and 365 controls were enrolled. Over a mean of 5-year follow-up, cause of death data were obtained from the Ministry of Health and Welfare in Taiwan. NPS were assessed using Neuropsychiatric Inventory Questionnaire (NPI-Q), and psychosis, mood, and frontal domain scores were determined. Survival analyses were conducted to determine the hazard ratio (HR) of death. Results: In controlled analyses, HR of death for AD was 2.19 (95% confidence interval [CI] = 1.29–3.71) compared with the control group, whereas no statistical significance was noted for the MCI group. A high NPI-Q score (above the median score) increased mortality risk for both the MCI and AD groups, with HRs of 2.32 (95% CI = 1.07–5.03) and 2.60 (95% CI = 1.51–4.47), respectively. Among NPI-Q domain scores, only high mood domain, but not psychosis or frontal domain, scores increased death risk for both the MCI (HR = 2.89, 95% CI = 1.00–8.51) and AD (HR = 2.59, 95% CI = 1.47–4.55) groups. Conclusion: Mortality risk is high for patients with AD. Not only for AD, patients with MCI presenting with NPS, particularly mood symptoms, have high death risk.