The effect of high-intensity use services on frequent emergency department attendance in England: controlled, interrupted, multicentre, time-series analysis of routinely collected electronic health records

BACKGROUND: The National Health Service in England has encouraged the development of specialised services for patients with high-intensity use of emergency departments: liaison psychiatry services in emergency departments and community services. AIMS: To evaluate the effect of different types of high-intensity use services on attendances at emergency departments, for those with 5 (HU5) or 10 (HU10) or more attendances in the previous 12 months, and the subset of this group with probable mental health problems, versus emergency departments without locality high-intensity use services. METHOD: A retrospective longitudinal study was conducted using nationally sourced data from 13 hospitals in England, spanning 1 April 2016 to 1 January 2020. An interrupted time-series analysis assessed the impact of three high-intensity use service models on weekly emergency department attendances: emergency department-based services with and without designated staffing, and community based services. Patients and clinicians contributed throughout the project. RESULTS: A total of 2 938 510 emergency department attendances were analysed. Statistically significant associations were identified between the implementation of community-based services and reductions in weekly attendances by HU10 patients (rate ratio 0.83, 95% CI 0.71-0.97), and HU5 and HU10 patients with mental health-related attendances (HU5 rate ratio 0.82, 95% CI 0.75-0.91; HU10 rate ratio 0.70, 95% CI 0.59-0.84). Emergency department-based services with designated staff were associated with a reduction in mental health-related attendances among HU10 patients (rate ratio 0.88, 95% CI 0.80-0.98). CONCLUSIONS: Services targeting patients with high-intensity use of emergency departments in England demonstrate promising potential in reducing emergency department attendances among this patient group. Community-based interventions show the most substantial impact, whereas hospital-based services often run by liaison psychiatry teams also contribute to reductions in those with high-intensity use with mental health issues. These findings support further development and expansion of tailored high-intensity use services across the country.