Psychiatric Comorbidities Affect the Hospitalization Course of Parkinson's Disease Patients: A Cross-Sectional Inpatient Study.

Objectives We aim to delineate the differences in demographic characteristics and hospitalization outcomes including the severity of illness, hospitalization length of stay (LOS) and cost, utilization of deep brain stimulation (DBS), and disposition in Parkinson's disease (PD) inpatients with psychiatric comorbidities versus without psychiatric comorbidities. Methods We conducted a cross-sectional study using the Nationwide Inpatient Sample (NIS), included 56,844 PD inpatients (age ≥40 years), and subdivided them by inpatients into those without psychiatric comorbidities (N = 38,629) and with psychiatric comorbidities (N = 18,471). We compared the distributions of demographic characteristics and hospitalization outcomes (severity of illness, utilization ofDBS, and disposition) by performing Pearson's chi-square test, and we measured the differences in continuous variables (i.e., age, LOS, and cost) by using the independent samples t-test.  Results A significantly higher proportion of PD inpatients with psychiatric comorbidities were female (44.4%) and white (83%) and had a moderate loss of functioning (48.8%) compared to those without psychiatric comorbidities. PD inpatients with psychiatric comorbidities had an increased mean LOS (4.7 days vs. 3.7 days, P <0.001) but a lower mean cost ($37,445 vs. $ 41,957, P <0.001). Also, there was a significantly lower utilization of DBS in PD inpatients with psychiatric comorbidities (19.2% vs. 26.9%, P <0.001) compared to those without psychiatric comorbidities, and an adverse disposition of transfer to a skilled nursing facility/intermediate care facility (47.1% vs. 39.6%, P <0.001) compared to PD inpatients without psychiatric comorbidities. Conclusion Although PD patients with psychiatric comorbidities had a moderate loss of functioning, there was significant underutilization of DBS. Meanwhile, psychiatric comorbidities among PD patients led to increased LOS and transfer to skilled facilities.