[S37.001] Low Diagnostic Accuracy of a Clinical Diagnosis of Early Parkinson's Disease: Findings of the Arizona Parkinson's Disease Consortium

Charles Adler,1Thomas Beach,2Joseph G. Hentz,1Holly Shill,2John Caviness,1Erika Driver-Dunckley,1Marwan Sabbagh,2Lucia Sue,2Sandra Jacobson,2Christine Belden,2Brittany Dugger,2Arizona Parkinson's Disease Consortium
1Scottsdale, AZ, USA, 2Sun City, AZ, USA

Objective: Determine the diagnostic accuracy of a clinical neurologic examination diagnosis of Parkinson's disease (PD) using neuropathological diagnosis as the gold standard.
Background: The accuracy of a clinical diagnosis of PD has significant impact on clinical care, clinical trials, and epidemiological/genetic/biomarker research studies.
Design/Methods: Data from the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND), an ongoing longitudinal clinical-neuropathological study, was used to determine the predictive value of an antemortem PD diagnosis, using two clinical diagnostic confidence levels, probable PD (ProbPD-responsive to dopaminergic medications) and possible PD (PossPD-never treated or not clearly responsive) and two diagnostic time points, first visit and final (postmortem) conference. For all calculations, the neuropathological diagnosis was used as the gold standard.
Results: At first visit of ProbPD with a disease duration less than 5 yrs, PD was neuropathologically confirmed in only 8/15 (53%) cases. In comparison, in ProbPD with a disease duration of at least 5 yrs at first visit, PD was neuropathologically confirmed in 72/82 (88%) cases. As a whole, of 97 subjects with ProbPD at the first visit 80 (82%) had neuropathologically confirmed PD. Of ProbPD at the final visit, 91/107 (85%) had neuropathologically confirmed PD. The clinical variables that improved diagnostic accuracy were medication response, motor fluctuations, dyskinesias and hyposmia. Of PossPD cases at first visit only 9/34 (26%) followed to autopsy had neuropathologically confirmed PD.
Conclusions: This study extends previous work on the diagnostic accuracy of a clinical diagnosis of PD and includes novel findings of less than 60% accuracy with shorter duration of disease and only 26% accuracy in untreated or not clearly responsive subjects. Therefore, caution is needed when interpreting clinical studies of PD that do not have autopsy confirmation and reinforce the need for a tissue or other diagnostic biomarker
Study Supported by: NINDS, NIA, Arizona Biomedical Research Commission, Michael J. Fox Foundation for Parkinson's Research, and Mayo Clinic Foundation.
Category - Movement Disorders: Parkinson's Disease

Wednesday, April 30, 2014 4:00 PM

S37: Platform Blitz: Clinical Aspects of Parkinson's Disease (4:00 PM-5:45 PM)


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