Causes of Death in People with Dementia from 2002 to 2015: A Nationwide Study

BACKGROUND: Dementia is associated with increased mortality. However, it is not clear whether causes of death in people with dementia have changed over time. OBJECTIVE: To investigate if causes of death changed over time in people with dementia compared to the general elderly population. METHODS: We included longitudinal data from nationwide registries on all Danish residents aged≥65 years to 110 years who died between 2002 to 2015. We assessed the annual frequency of dementia-related deaths (defined as a dementia diagnosis registered as a cause of death) and of underlying causes of death in people registered with dementia compared to the general elderly population. RESULTS: From 2002 to 2015, 621,826 people died, of whom 103,785 were diagnosed with dementia. During this period, the percentage of dementia-related deaths increased from 10.1% to 15.2% in women, and from 6.3% to 9.5% in men in the general elderly population. From 2002 to 2015, dementia became the leading, registered underlying cause of death in people diagnosed with dementia. Simultaneously, a marked decline in cardiovascular and cerebrovascular deaths was observed in people with and without dementia. CONCLUSION: This is the first study to investigate if the causes of death change over time in people diagnosed with dementia compared with the general elderly population. The increase in the registration of dementia as an underlying cause of death could reflect increasing awareness that dementia is fatal.