Increases in institutionalization, healthcare resource utilization, and mortality risk associated with Parkinson disease psychosis: Retrospective cohort study

Introduction: Patients with Parkinson disease (PD) often develop psychosis (P). The association of PDP with death and long-term custodial care (CC) has not been well studied. Methods: Medicare Parts A, B, and D data, 2007-2015, were used to define cohorts of PD and PDP patients. PD was defined by >= 2 ICD-9-CM codes (332.0x) at least 30, but no more than 365, days apart, and PDP by >= 2 codes for psychotic symptoms. Outcomes were CC use, defined as nursing home stays of > 100 consecutive days, and death. To compare the association of PDP with outcomes, PDP patients were matched to PD patients without psychosis. Results: Within 1 year of PDP diagnosis, 12.1% of PDP patients used CC, versus 3.5% of non-PDP patients 1 year after the matching date; corresponding percentages at 5 years were 25.8% and 10.0%. Cumulative incidence curves for CC and for death differed significantly (P < 0.0001). PDP was associated with RRs of 3.38 (95% CI, 2.93-3.90) for CC and 1.34 (1.23-1.45) for death. Other factors associated with CC were age (3.57, 2.08-6.14, age >= 90 versus <= 70 years) and female sex (1.37, 1.18-1.58). Female sex was associated with a lower RR for death (0.76, 0.70-0.82). Health care utilization and costs were substantially higher for PDP than for non-PDP patients. Conclusion: In PD patients, psychosis was associated with a more than 3-fold increased risk of CC and a nearly one-third increased risk of death. Women entered CC more often than men, likely because they lived longer in the setting of PD.