LAUSR

OBJECTIVES Evidence regarding the relationships between patient, hospital, and regional factors and early unplanned readmission (short-term outcome) in patients with bipolar disorder is lacking. This study aimed to examine risk factors associated with early unplanned readmission in patients with bipolar disorder. METHOD We retrospectively analyzed adult bipolar patients (ICD-10; F31) between April 2012 and March 2014 in the Japanese Diagnosis Procedure Combination database. We examined factors affecting the 30-day unplanned readmission using multivariable logistic regression analysis. RESULTS A total of 2688 patients admitted to psychiatric beds were included. Multivariate analysis showed that unchanged or exacerbation discharge outcome (adjusted odds ratio [aOR]: 1.93; 95% confidence interval [CI]: 1.06-3.51, p = 0.031), unplanned or urgent admission settings (aOR: 1.51; 95% CI: 1.00-2.26, p = 0.048), physical comorbidity (chronic pulmonary disease) (aOR: 4.74; 95% CI: 1.30-17.29, p = 0.018), presence of psychiatric acute-care beds (aOR: 1.72; 95% CI: 1.02-2.87, p = 0.040), and intermediate-level hospital psychiatric staffing (aOR: 1.82; 95% CI: 1.14-2.91, p = 0.012) were significantly associated with higher early unplanned readmission, while higher density of psychiatrists in the area (aOR: 0.50; 95% CI: 0.29-0.87, p = 0.014) was significantly associated with lower early unplanned readmission. CONCLUSIONS The results suggest that not only careful management of high-risk patients but also consideration of functional differentiation in psychiatric inpatient care, psychiatric resource allocation, and follow-up support for patients with bipolar disorder are needed for reducing the early unplanned readmission rate.