Abstract
Identification of factors predicting and driving mortality in PD is important for patient information, disease management, and design of future clinical trials. This study included newly diagnosed PD patients and normal controls (NC) from a population-based study with repeated assessments over a 10-year period. We used the Kaplan-Meier method to estimate survival, Cox proportional hazards regression models to identify baseline risk factors of mortality, and Cox regression models with time-dependent covariates to evaluate the impact of four clinical milestones of advanced PD (visual hallucinations, recurrent falls, dementia, and nursing home placement) on mortality risk. During the 10-year study, 65 (34.2%) of 190 patients and 25 (12.3%) of 203 NC died, with an unadjusted hazard ratio (HR) of 2.85 (95% CI 1.80-4.52) and a HR of 2.48 (95% CI 1.55-3.95) when adjusted for confounders, including comorbidities. Higher age, more severe motor impairment, and postural instability-gait difficulty (PIGD) phenotype were independent baseline predictors of mortality. Each clinical milestone alone more than doubled the risk of death and had a cumulative effect on mortality, with a HR of 10.83 (95% CI 4.39-26.73) in those experiencing all four milestones. PD patients have an increased mortality risk that is disease-related and becomes evident early during the course of the disease. While motor severity and PIGD phenotype were early risk factors of mortality, clinical milestones signaled a substantially increased risk of death later during the disease course, highlighting their potential significance in clinical disease staging and prognosis.