Mobile Crisis Outreach and Emergency Department Utilization: A Propensity Score-matched Analysis

Mental health and substance use disorder (MHSUD) patients in the emergency department (ED) have been facing increasing lengths of stay due to a shortage of inpatient beds. Previous research indicates mobile crisis outreach (MCO) reduces long ED stays for MHSUD patients. Our objective was to assess the impact of MCO contact on future ED utilization.

We conducted a retrospective chart review of patients presenting to a large Midwest university ED with an MHSUD chief complaint from 2015-2018. We defined the exposure as those who had MCO contact and any MHSUD-related ED visit within 30 days of MCO contact. The MCO patients were 2:1 propensity score-matched by demographic data and comorbidities matched to patients with no MCO contact. Outcomes were all-cause and psychiatric-specific reasons for return to the ED within one year of the index ED visit. We report descriptive statistics and odds ratios (OR) to describe the difference between the two groups, and hazard ratios (HR) to estimate the risk of return ED visit.

The final sample included 106 MCO and 196 non-MCO patients. The MCO patients were more likely to be homeless (OR 14.8; 95% confidence interval [CI],1.87, 117), less likely to have adequate family or social support (OR 0.51; 95% CI, 0.31, 0.84), and less likely to have a hospital bed requested for them in the index visit by ED providers (OR 0.50; 95% CI, 0.29, 0.88). For those who returned to the ED, the median time for all-cause return to the ED was 28 days (interquartile range [IQR]: 6-93 days) for the MCO patients and 88 days (IQR: 20-164 days) for non-MCO patients. The risk of all-cause return to the ED was greater among MCO patients (67%) compared to non-MCO patients (49%) (adjusted HR: 1.66; 95% CI, 1.22, 2.27).

The MCO patients had less family and social support; however, they were less likely to require hospitalization for each visit, likely due to MCO involvement. Patients with MCO contact presented to the ED more frequently than non-MCO patients, which implies a strong linkage between the ED and MCO in our community. An effective referral to community service from the ED and MCO and collaboration could be the next step to improve healthcare utilization.