Determinants of High Psychiatric Utilization at a Large Urban Safety-Net Hospital.

Research indicates that high utilizers of the health care system are more likely to have mental illness, to be from socially disadvantaged groups, and to have limited access to community-based services. In this retrospective study, three definitions of high utilization were examined: (1) across time: non-high utilization versus high-utilization, (2) single year versus multi-year, and (3) year-to-year. Univariate logistic regression models were fit to a set of 20 theory-selected predictors of high utilization. An optimal multiple predictor model was then derived via penalized multiple logistic regression (via elastic net, a machine learning algorithm). Three factors were identified in the optimized model as increasing the likelihood of high utilization: having a diagnosis of schizophrenia, having a co-occurring personality disorder diagnosis, and having less than a high school education. Given the complex needs of psychiatric high utilizers, innovative approaches should be considered to improve patient outcomes and reduce costly psychiatric hospitalizations.