Serious Mental Illness and Health-Related Factors Associated with Regional Emergency Department Utilization

Frequent emergency department (ED) utilization is an indicator of unmet health and social needs, especially among patients with mental and physical health problems. The authors aimed to characterize frequent ED utilizers and drivers of multiple ED use, including presence of serious mental illness (SMI), across 2 large health care systems in Northern California. Using electronic health records and a data-sharing platform, a cross-sectional analysis was conducted of patients aged 18+ years with >= 10 ED visits in 2016. Logistic regression was used to determine factors associated with multiple ED use versus single ED use. Among the 8036 patients who met inclusion criteria, the mean age was 55.9 years (95% CI = 55.5-56.4), 53% were female, 54% were non-Hispanic white, and 38% had any SMI. Overall, 51% of patients were single ED utilizers. Patients ages >= 65 years were less likely to use multiple EDs compared to younger patients (ages 18-23) (OR = 0.3, 95% CI = 0.2-0.4). African Americans exhibited more than 3 times the likelihood of multi-ED use compared to non-Hispanic whites (OR = 3.8, 95% CI = 3.3-4.3). A diagnosis of any SMI (OR = 2.3 [95% CI: 2.1-2.6]), major depressive disorder (OR = 1.3, 95% CI = 1.1-1.4), schizophrenia (OR = 2.1, 95% CI = 1.6-2.6), or suicidal attempts/ideation (OR = 2.7, 95% CI = 2.1-3.6) was significantly associated with increased likelihood of multi-ED use. Findings indicate heterogeneity in regional utilization patterns among frequent ED utilizers, with mental illness increasing the likelihood of multi-ED use.