The estimation and validation of pre-senile dementia in Germany using health care data of the AOK

Thomas Fritze, German Center for Neurodegenerative Diseases (DZNE)

People suffering from pre-senile dementia (onset before age 65) face different problems compared to patients with senile dementia. The early onset of the disease is affecting people who are still actively engaged in the labor force and in raising children. Different needs regarding to care and service make it essential to know more about this illness. The objective of our study is to estimate the prevalence of pre-senile dementia in Germany. We aim to validate the estimates with regards to risk factors and the type of physician that has given the underlying diagnosis. Claims data of the AOK, the largest German health insurance, provide information of 30,276 persons aged 45-64 with a dementia diagnosis according to ICD-10 in 2007. The population at risk consists of about 6.4 million persons. We start by calculating the prevalence of an overall dementia indicator and of sub-diagnoses. Negative binomial regression models are then used to define the role of risk factors and the diagnosing physician type. We found a prevalence of pre-senile dementia of 475 cases per 100,000 persons for the age group 45-64. About one third of the total prevalence is related to a diagnosis by a neuropsychiatrist during the observation period. The sub-diagnoses reveal similar patterns: 24% of 302 cases for unspecified dementia and 37% of 110 cases for vascular dementia are related to diagnoses by specialists; for Alzheimer’s it is 58% of 80 cases. Taking into account several risk factors and the presence of a neuropsychiatrist reveal a probable valid prevalence. The estimated prevalence can be extrapolated to the German population and reveals that currently up to 120,000 persons suffer from pre-senile dementia. The results offer the chance to supply adequate care for a population with special needs.