Twenty-Three Year Mortality in Parkinson’s Disease: A Population-Based Prospective Study (NEDICES)

Parkinson's disease (PD) is a prevalent neurodegenerative disorder in older adults, yet its long-term mortality impact remains inadequately defined. This study builds on prior findings from the Neurological Disorders in Central Spain (NEDICES) cohort, extending mortality analysis to a 23-year follow-up within a Spanish population-based sample. This prospective cohort study included 5,278 individuals aged 65 years and older. Conducted in two waves (baseline and follow-up), it identified 81 prevalent PD cases at baseline (1994-95) and 30 incident (premotor) cases at follow-up (1994-95). Mortality was tracked for up to 23 years, with Cox proportional hazard models used to estimate mortality hazard ratios (HRs), adjusted for demographic and clinical variables. Among 111 PD cases, 109 (98.2%) died during follow-up, compared to 4,440 (86.8%) of 5,114 without PD. PD was associated with a significantly increased mortality risk (adjusted HR=1.62; 95% confidence interval [CI]=1.31–2.01). Individuals with both PD and dementia had an even higher risk (HR=2.19; 95% CI=1.24–3.89). Younger-onset PD (<65 years) showed heightened mortality risk (HR=2.11; 95% CI=1.22–3.64). Cardiovascular or cerebrovascular diseases were the leading causes of death in both PD and non-PD participants. PD was significantly more often listed as the primary cause of death in PD individuals compared to the reference group (14.7% vs. 0.4%, p<0.001). PD significantly increases mortality risk over 23 years, particularly among those with early onset and dementia. These findings support a multidisciplinary PD care approach that addresses both motor and non-motor symptoms to improve long-term outcomes.