Declining incidence but little change in years lived with dementia in two German cohorts diagnosed with dementia in 2006/2008 and 2016/2018

Background We examined whether changes in dementia incidence and mortality have led to changes in the average number of years lived with and without dementia over a ten-year period in Germany.

Methods We calculated dementia rates using two samples of people aged 65 + from a German health insurance company, each comprising more than 100,000 people in 2006/08 and 2016/18. We examined time trends using negative binomial regression models and estimated average life expectancy (ALE) for people with and without dementia by fitting a three-stage Markov health-disease model.

Results Dementia incidence rates decreased by 7.3% in men and by 9.7% in women. Dementia mortality rates fell by 12% in men but did not change significantly in women. Non-dementia mortality rates fell by 7% in both men and women. The combined changes resulted in stable total ALE in men and increasing total ALE in women, whereas ALE with dementia increased in men and remained stable in women.

Conclusions The observed decline in dementia incidence did not translate into a reduction in the burden of the disease.