Incidence and prevalence of Parkinson's disease in Buenos Aires City, Argentina

Background and purpose: Epidemiologic studies of incidence and prevalence in Parkinsons Disease (PD) show highly variable results. Despite the large number of studies performed worldwide during the last decades, little is known about its prevalence in South America and no incidence studies have been performed. The goal of this study is to assess the incidence and prevalence of PD in a health maintenance organization from Buenos Aires City, the capital city of Argentina. Methods: The population were all members of the Plan de Salud, Hospital Italiano de Buenos Aires, a large prepaid health medical organization in Buenos Aires. From 1 January 2003 to 31 December 2008 patients diagnosed with PD according to Brain Bank of London diagnostic criteria were identified retrospectively. Incidence density was calculated with 95% confidence interval. Results: Hundred and forty thousand people were followed for a total of 754 082 person-years. A total of 239 incident cases of PD were identified. Crude incidence density was 31.2/100 000 person-years. Prevalence was 394/100 000 in the population older than 40 years. Male to female ratio was 1.31. Conclusions: This is the first study in South America that estimates the incidence of PD. Our results are consistent with other studies from other regions using similar methodologies.