The progression of Parkinson’s disease is highly variable from patient to patient. It is currently not possible to predict the future course of Parkinson’s disease from early physical signs or symptoms.
In an analysis of the DATATOP (Deprenyl And Tocopherol Antioxidative Therapy Of Parkinsonism) clinical trial database we have identified four factors associated with the time interval from disease onset to the development of disability requiring drug treatment for Parkinson’s disease: degree of symmetry of symptoms, having tremor as an initial symptom, side of onset of symptoms and smoking history. We will test the reproducibility of these findings using the PRECEPT (Parkinson Research Examination of CEP-1347 Trial) clinical trial database.
Both DATATOP and PRECEPT were clinical trials enrolling at least 800 subjects with very early Parkinson’s disease. We will also test the association between the variables of interest and changes in striatal [123I]beta-CIT uptake, a neuroimaging measure of dopaminergic nerve terminal function in the brain, to test the biological relevance of the observed clinical associations. If our preliminary results are confirmed, we will have identified risk factors for rate of progression of Parkinson’s disease that can be measured early in the disease process.
Final Outcome
From the DATATOP dataset, Dr. Marras demonstrated that tremor as an initial symptom predicted slower disease progression. While not all results from DATATOP were replicated in PRECEPT (potentially due to changes in treatment philosophy as outcome measure is subjective), tremor as an initial symptom predicted slower progression in both populations. Furthermore, older subjects took longer to require dopaminergic therapy. No factors studied were associated with change in beta-CIT uptake. This may reflect the fact that requiring drug therapy for Parkinson's disease reflects not only biological progression of disease but also social and occupational demands and attitudes toward treatment.