Psychiatric patient boarding in emergency department (ED) is a severe and growing problem. In July 2013, Minnesota implemented a law requiring jailed persons committed to state psychiatric facilities be transferred within 48-h of commitment. This study aims to quantify the effect of this law on a large ED's psychiatric patient flow.

A pre- and post- comparison of 2011–2015 ED length of stay (LOS) for adult psychiatric patients was performed using electronic medical record data. Comparisons of the median LOS were assessed using a segmented regression model with time series error, and risk differences (RD) were used to determine changes in the proportion of patients with LOS ≥3 and ≥5days. Changes in patient disposition proportions were assessed using risk ratios.

The median ED LOS for patients admitted for psychiatric care increased by 5.22h from 2011 to 2015 (95% CI: (4.33, 7.15)), while the frequency of patient encounters remained constant. Although no significant difference in the rate of ED LOS increase was found pre- and post- implementation, the proportion of adults with LOS ≥3days and ≥15days increased (RD 0.017 (95% CI: (0.013, 0.021)); 0.002 (95% CI: (0.001,0.004)), respectively).

The proportion of ED adult psychiatric patients experiencing prolonged LOS increased following the implementation of a statewide law requiring patients committed through the criminal justice system be transferred to a state psychiatric hospital within 48h. Identifying characteristics of subsets of psychiatric patients disproportionally affected could suggest focused healthcare system improvements to improve ED psychiatric care.