Comorbid Depression and Psychosis in Parkinson's Disease: A Report of 62,783 Hospitalizations in the United States

Background Depression and psychosis are common comorbidities that significantly affects the quality of life and disease outcomes in Parkinson's disease (PD) patients. Objective The aim of this study was to analyze and discern the differences in the hospitalization outcomes, comorbidities, and utilization of deep brain stimulation (DBS) in PD patients with comorbid depression and comorbid psychosis. Methods We used the Nationwide Inpatient Sample (2010-2014) and identified PD as a primary diagnosis (N = 62,783), and depression (N = 11,358) and psychosis (N = 2,475) as co-diagnosis using the International Classification of Diseases, Ninth Revision (ICD-9) codes. Pearson's chi-square test and independent-sample -test were used for categorical data and continuous data, respectively. Results White male, older age, and comorbid psychosis were significantly associated with higher odds of having major severity of illness in PD inpatients. The mean length of stay (LOS) was higher in PD patients with psychosis compared to PD with depression (7.32 days vs. 4.23 days; < 0.001), though the mean total charges of hospitalization were lower in psychosis ($31,240 vs. $38,581; < 0.001). Utilization of DBS was lower in PD patients with psychosis versus with depression (3.9% vs. 24.3%; < 0.001). Conclusion Psychiatric comorbidities are prevalent in PD patients and are associated with more disease severity, impaired quality of life, and increased use of healthcare resources (higher LOS and cost). They should be considered an integral part of the disease, and a multidisciplinary approach to managing this disease is crucial to improve the health-related quality of life of PD patients.