Factors associated with hospitalization of adult psychiatric patients: cluster analysis

Objective: Factors associated with acute admission to inpatient psychiatric wards have been difficult to replicate, possibly reflecting methodological limitations of analyzing individual variables. The objective of this analysis was to identify factors associated with hospitalization at an inpatient psychiatric unit using cluster analytic methods. Methods: Demographic, admission and treatment data for all admissions to a single inpatient unit in 2010 were collected retrospectively. Cluster analysis was performed using Ward's method. Results: The initial clustering identified a high suicidality/crisis group, which then gave two further subclusters, an internalizing one characterized by affective symptoms and an externalizing one characterized by intoxication at admission, and a population with poor medication compliance that included most cases of psychosis. These subclusters had different clinical and demographic characteristics, different rates of hospital readmission and different durations of stay. Conclusions: Cluster analysis may be a useful exploratory technique to assist in planning and developing services for adult patients needing admission to a psychiatric hospital.