Predictors of Survival in Patients With Parkinson Disease

Abstract

To determine the life expectancy of patients with Parkinson disease (PD) in the United States and identify demographic, geographic, and clinical factors that influence survival. Retrospective cohort study of 138 000 Medicare beneficiaries with incident PD who were identified in 2002 and followed up through 2008. Confounder-adjusted 6-year risk of death as influenced by 3 groups of factors: (1) race, sex, and age at diagnosis; (2) geography and environmental factors; and (3) clinical conditions. We examined hospitalization diagnoses in patients with terminal PD and compared PD mortality with that of other common diseases. Thirty-five percent of patients with PD lived more than 6 years. Sex and race significantly predicted survival; patients who were female (HR [hazard ratio], 0.74; 95% CI, 0.73-0.75), Hispanic (HR, 0.72; 95% CI, 0.65-0.80), or Asian (HR, 0.86; 95% CI, 0.82-0.91) had a lower adjusted risk of death than white men. Dementia, diagnosed in 69.6% of cases and most often in African American patients (78.2%) and women (71.5%), was associated with a greater likelihood of death (HR, 1.72; 95% CI, 1.69-1.75). Parkinson disease mortality was greater than that of many common life-threatening diseases. Patients with terminal PD were hospitalized frequently for cardiovascular disease (18.5%) and infection (20.9%) but rarely for PD (1.0%). Regional survival rates were similar but patients with PD living in urban high industrial metal emission areas had a slightly higher adjusted risk of death (HR, 1.19; 95% CI, 1.10-1.29). Demographic and clinical factors impact PD survival. Dementia is highly prevalent in patients with PD and is associated with a significant increase in mortality. More research is needed to understand whether environmental exposures influence PD course or survival.