Predictors of Institutionalization in Patients with Alzheimer's Disease in South Korea

Abstract

BACKGROUND AND PURPOSE: We investigated predictors of institutionalization in patients with Alzheimer's disease (AD) in South Korea. METHODS: In total, 2,470 patients with AD aged 74.5+/-7.8 years (mean+/-standard deviation, 68.1% females) were enrolled from November 2005 to December 2013. The dates of institutionalization were identified from the public Long-Term-Care Insurance program in January 2014. We used a Cox proportional-hazards model to identify predictors for future institutionalization among characteristics at the time of diagnosis in 2,470 AD patients. A similar Cox proportional-hazards model was also used to investigate predictors among variables that reflected longitudinal changes in clinical variables before institutionalization in 816 patients who underwent follow-up testing. RESULTS: A lower Mini Mental State Examination score [hazard ratio (HR)=0.95, 95% confidence interval (CI)=0.92-0.97] and higher scores for the Clinical Dementia Rating and Neuro-Psychiatric Inventory (HR=1.01, 95% CI=1.00-1.01) at baseline were independent predictors of institutionalization. The relationship of patients with their main caregivers, presence of the apolipoprotein E e4 allele, and medication at baseline were not significantly associated with the rate of institutionalization. In models with variables that exhibited longitudinal changes, larger annual change in Clinical Dementia Rating Sum of Boxes score (HR=1.15, 95% CI=1.06-1.23) and higher medication possession ratio of antipsychotics (HR=1.89, 95% CI=1.20-2.97) predicted earlier institutionalization. CONCLUSIONS: This study shows that among Korean patients with AD, lower cognitive ability, higher dementia severity, more-severe behavioral symptoms at baseline, more-rapid decline in dementia severity, and more-frequent use of antipsychotics are independent predictors of earlier institutionalization.