Falling incidence of Parkinson's disease in Germany

Idiopathic Parkinson's disease (IPD) is a progressive neurodegenerative disorder that is strongly associated with age. The aim of the present study was to describe current sex- and age-specific trends and regional differences in the incidence of IPD diagnosed in older people in Germany.

This study was based on nationwide outpatient claims and drug prescription data from the German Statutory Health Insurance, covering approximately 87% of the general population. We conducted a cohort study in patients aged 50 years or older with observation time of at least 4 years. To assess the robustness of nationwide annual IPD incidence trends from 2013 to 2019, three case definitions with varying levels of stringency regarding coded outpatient diagnoses and drug prescriptions were applied.

In 2019, the population at risk comprised 30,575,726 persons. Using the primary and most specific case definition, annual age- and sex-standardized cumulative IPD incidence decreased stepwise from 137 (2013) to 106 (2019) new cases per 100,000 persons. The decline in incidence was seen in both sexes, in all age groups and in the majority of German regions. The relative decrease (2013-2019) in the annual age- and sex-standardized IPD incidence varied from 23% to 28% among case definitions.

Our findings indicate a nationwide decline in the age- and sex-standardized incidence of IPD from 2013 to 2019 in Germany. This trend was consistent using different case definitions. Further research is needed to elucidate the factors underlying this trend.