Developing consensus among movement disorder specialists on clinical indicators for identification and management of advanced Parkinson’s disease: a multi-country Delphi-panel approach

To provide an overview on the prevalence and incidence of Parkinson's disease (PD) in selected European countries. PD is a common disease of unknown etiology. Accurate information on the epidemiology of PD is critical to inform health policy. An aging population will lead to more patients with PD; thus, the high financial burden PD places on society will increase. A systematic literature search was performed to identify studies on the prevalence and incidence of PD in the following European countries: Austria, the Czech Republic, France, Germany, Italy, The Netherlands, Portugal, Spain, Sweden and United Kingdom. Only published studies were included. Abstracts, reviews, meta-analyses and letters to the editor were excluded. There were no language restrictions. Data were extracted using a standardized assessment form, and evidence tables were used to systematically report and compare the data. Of 39 identified studies, most (87%) reported estimates of PD prevalence rates, while only a few (13%) reported estimates of PD annual incidence rates. Crude prevalence rate estimates ranged from 65.6 per 100,000 to 12,500 per 100,000 and annual incidence estimates ranged from 5 per 100,000 to 346 per 100,000. No publications could be identified for Austria or the Czech Republic. The observed variations in prevalence and incidence rates may result from environmental or genetic factors, but might also be a consequence of differences in methodologies for case ascertainment, diagnostic criteria, or age distributions of the study populations. The comparability of existing studies is limited.