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

Background: Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders among older adults, yet its long-term impact on mortality within population-based cohorts remains insufficiently characterized. This study leverages data from the Neurological Disorders in Central Spain (NEDICES) cohort to provide a comprehensive 23-year mortality analysis in a Spanish population. Methods: In this prospective cohort study, 5278 individuals aged 65 years and older were evaluated across two waves: baseline (1994-1995) and follow-up (1997-1998). At baseline, 81 prevalent PD cases were identified, while 30 incident cases, likely in the premotor phase at baseline, were detected during follow-up. Mortality was tracked over 23 years, and Cox proportional hazard models were employed to estimate hazard ratios (HRs) for mortality, adjusting for relevant demographic and clinical variables. Results: Fifty-three individuals from the cohort in the reference group (without PD) were excluded due to unreliable mortality data. Among 111 PD cases, 109 (98.2%) died during follow-up compared to 4440 (86.8%) of 5114 without the disease. PD was associated with a significantly increased mortality risk (adjusted HR = 1.62; 95% confidence interval [CI] = 1.31-2.01). Patients with both PD and dementia had an even higher risk (HR = 2.19; 95% CI = 1.24-3.89). Early-onset PD (<65 years) showed heightened mortality risk (HR = 2.11; 95% CI = 1.22-3.64). Cardiovascular and 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 patients compared to the reference group (14.7% vs. 0.4%, p < 0.001). Conclusions: PD significantly increases mortality risk over 23 years, particularly among those with early onset and dementia. These findings underscore the importance of a multidisciplinary approach to PD care, targeting both motor and non-motor symptoms to enhance long-term outcomes.