Differential impact of individual autonomic domains on clinical outcomes in Parkinson's disease.

Introduction: While autonomic failure is a well-known prognostic factor for more aggressive disease progression in Parkinson's disease (PD), with a three- to sevenfold higher risk of dementia and death within 10 years after the diagnosis, the individual impact of cardiovascular, gastrointestinal, urogenital, thermoregulatory, and pupillomotor autonomic domains on PD clinical outcomes remains unclear.

Objectives: We sought to determine the 5-year risk of developing dementia, falls, postural instability, dysarthria, and dysphagia in PD patients with and without autonomic impairment at baseline and to assess the joint and individual association of each autonomic domain on these key functional outcomes. In addition, we aimed to determine the impact of each autonomic domain on activities of daily living (ADLs) and health-related quality of life (HRQoL).

Methods: We enrolled 65 consecutive PD patients in a 5-year cohort study involving standardized evaluations of autonomic symptoms, orthostatic hypotension, and motor and non-motor features, including cognitive function. Associations were estimated as odds ratio and adjusted for PD duration, age, and baseline motor impairment.

Results: Cardiovascular dysautonomia was associated with a sevenfold higher risk of developing dementia (95%CI: 1.154-50.436; p = 0.035) and a fivefold higher risk of falls (95%CI: 1.099-18.949; p = 0.039), as well as significantly higher impairment in ADLs (p = 0.042) and HRQoL (p = 0.031). No relevant associations were found between the other autonomic domains and these outcomes.

Conclusions: Cardiovascular dysautonomia, but not other domains, showed an association with worse 5-year clinical outcomes in PD. Our data suggest a specific role for cardiovascular autonomic dysregulation in the pathogenic mechanisms of PD progression.