Mortality Risk after Dementia Diagnosis by Dementia Type and Underlying Factors: A Cohort of 15,209 Patients based on the Swedish Dementia Registry

Abstract

BACKGROUND: Knowledge on survival in dementia is crucial for patients and public health planning. Most studies comparing mortality risk included few different dementia diagnoses. OBJECTIVES: To compare mortality risk in the most frequent dementia disorders in a large cohort of patients with an incident diagnosis, adjusting for potential confounding factors. METHODS: 15,209 patients with dementia from the national quality database, Swedish Dementia Registry (SveDem), diagnosed in memory clinics from 2008 to 2011, were included in this study. The impact of age, gender, dementia diagnosis, baseline Mini-Mental State Examination (MMSE), institutionalization, coresidency, and medication on survival after diagnosis were examined using adjusted hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: During a mean follow-up of 2.5 years, 4,287 deaths occurred, with 114 (95% CI 111-117) deaths/1,000 person-years. Adjusted HR of death for men was 1.56 (95% CI 1.46-1.66) compared to women. Low MMSE, institutionalization, and higher number of medications were associated with higher HR of death. All dementia diagnoses demonstrated higher HR compared to Alzheimer's disease, with vascular dementia presenting the highest crude HR. After adjusting, frontotemporal dementia had the highest risk with a HR of 1.91 (95% CI 1.52-2.39), followed by Lewy body dementia (HR 1.64; 95% CI 1.39-1.95), vascular dementia (HR 1.55; 95% CI 1.42-1.69), Parkinson's disease dementia (HR 1.47; 95% CI 1.17-1.84), and mixed Alzheimer's disease and vascular dementia (HR 1.32; 95% CI 1.22-1.44). CONCLUSION: Worse cognition, male gender, higher number of medications, institutionalization, and age were associated with increased death risk after dementia diagnosis. Adjusted risk was lowest in Alzheimer's disease patients and highest in frontotemporal dementia subjects.