Determinants of Boarding of Patients with Severe Mental Illness in Hospital Emergency Departments.

Background: Boarding of patients in hospital emergency departments (EDs) occurs routinely across the U.S. ED patients with behavioral health conditions are more likely to be boarded than other patients. However, the existing literature on ED boarding of psychiatric patients remains largely descriptive and has not empirically related mental health system capacity to psychiatric boarding. Nor does it show how the mental health system could better address the needs of populations at the highest risk of ED boarding.

Aims of the study: We examined extent and determinants of "boarding" of patients with severe mental illness (SMI) in hospital emergency departments (ED) and tested whether greater mental health system capacity may mitigate the degree of ED boarding.

Methods: We linked Oregon's ED Information Exchange, hospital discharge, and Medicaid data to analyze encounters in Oregon hospital EDs from October 2014 through September 2015 by 7,103 persons aged 15 to 64 with SMI (N = 34,207). We additionally utilized Medicaid claims for years 2010-2015 to identify Medicaid beneficiaries with SMI. Boarding was defined as an ED stay over six hours. We estimated a recursive simultaneous-equation model to test the pathway that mental health system capacity affects ED boarding via psychiatric visits.

Results: Psychiatric visits were more likely to be boarded than non-psychiatric visits (30.2% vs. 7.4%). Severe psychiatric visits were 1.4 times more likely to be boarded than non-severe psychiatric visits. Thirty-four percent of psychiatric visits by children were boarded compared to 29.6% for adults. Statistical analysis found that psychiatric visit, substance abuse, younger age, black race and urban residence corresponded with an elevated risk of boarding. Discharge destinations such as psychiatric facility and acute care hospitals also corresponded with a higher probability of ED boarding. Greater supply of mental health resources in a county, both inpatient and intensive community-based, corresponded with a reduced risk of ED boarding via fewer psychiatric ED visits.

Discussion: Psychiatric visit, severity of psychiatric diagnosis, substance abuse, and discharge destinations are among important predictors of psychiatric ED boarding by persons with SMI. A greater capacity of inpatient and intensive community mental health systems may lead to a reduction in psychiatric ED visits by persons with SMI and thereby decrease the extent of psychiatric ED boarding.

Implications for health policies: Continued investment in mental health system resources may reduce psychiatric ED visits and mitigate the psychiatric ED boarding problem.