Clinical criteria for the switch of treatment strategies in Parkinsonʹs disease

Along the years the treatment of Parkinsonʹs disease with L-dopa has revealed unfavorable effects in general after 5–10 years. This has led to the present criteria for treatment of de novo patients that mainly relay on the age, the general strategy being to delay the use of L-dopa as long as possible. However, this practical approach lacks a scientific basis. In a retrospective study data of 155 patients with Parkinsonʹs disease were analyzed with the goal of finding a clinical marker for the critical time point when L-dopa needs to be administrated. The clinical stage of the patients was assessed using the Hoehn and Yahr (H&Y) scale and the severity of the symptoms was measured using the UPDRS score. The results show that there was no relationship between the age of the patients and the therapy (L-dopa vs. no L-dopa) with regard to the clinical outcome. A significant interaction was found however, between the clinical stage (H&Y) and the therapy. Further analysis of this interaction showed that in the H&Y Stages 1–2.5 the UPDRS scores were lower in the patient groups treated without L-dopa. Remarkably, in the H&Y stages 3 and higher the UPDRS scores were lower in the patient groups treated with L-dopa. These results suggest that the clinical stage of the disease (H&Y) might be a better criterion than the age for the time point when L-dopa needs to be administered in de novo patients.