Survival and Progression in Synucleinopathy Phenotypes With Parkinsonism: A Population-Based Study.
To compare survival by the presenting parkinsonism symptoms at diagnosis among patients with incident clinically diagnosed synucleinopathies. Using the Rochester Epidemiology Project medical records-linkage system, we identified all persons residing in Olmsted County, Minnesota, who received a diagnostic code of parkinsonism from January 1, 1991, through December 31, 2010. A movement disorder specialist reviewed the complete medical records of each individual to confirm the presence of parkinsonism, determine the type of synucleinopathy, and identify the onset dates of each cardinal symptom (tremor at rest, bradykinesia, rigidity, and impaired postural reflexes). We determined the median time from age at diagnosis to death or censoring (June 30, 2015) for each presenting symptom and the age- and sex-adjusted risk of death. From 1991 through 2010, a total of 433 individuals had a synucleinopathy diagnosed (301 [69.5%], Parkinson disease; 68 [15.7%], dementia with Lewy bodies; 52 [12.0%], Parkinson disease dementia; and 12 [2.8%], multiple systems atrophy with parkinsonism). Overall, the risk of death in the tremor-predominant group was less than that in the bradykinesia/rigidity-only group (hazard ratio [HR], 0.59; 95% CI, 0.40-0.87; P=.007). Similarly, risk of death in the bradykinesia/rigidity-only group was significantly greater than in the tremor-predominant group (HR, 1.75; 95% CI, 1.23-2.51; P=.002) and compared with tremor before bradykinesia (HR, 1.75; 95% CI, 1.24-2.47; P=.001). Patients with tremor as a presenting symptom have longer survival. In contrast, the presence of bradykinesia/rigidity as a presenting symptom correlates with reduced survival across all types of synucleinopathies.