Authors' objectives: Emergency ambulance services aim to respond to patients calling with urgent healthcare needs, prioritising the sickest. A small minority make high use of the service, which raises clinical and operational concerns. Multidisciplinary ‘case management’ approaches combining emergency, primary and social care have been introduced in some areas but evidence about effectiveness is lacking. Ambulance services, an integral part of the UK’s NHS, are under sustained pressure, with emergency calls increasing annually by at least 6%. A small minority of people make high use of the emergency ambulance service. These callers often have complex needs and may be at high risk of mental health or other crises; providing an emergency ambulance response to them has operational implications for ambulance services and may not meet their needs. The standard response to these callers can be punitive and may shift unmet demand from one part of the health and social care system to another, with concomitant resource implications. In some areas within ambulance services, multidisciplinary approaches provided with input from emergency, primary and social care – known as case management – have been introduced. However, evidence supporting the use of this approach for the care of patients who frequently call the emergency ambulance service is lacking. To address this gap, the STRETCHED study was designed as a mixed-methods evaluation using anonymised linked routine data outcomes to evaluate the effectiveness, safety and efficiency of case management for the care of this patient group. The objectives of the STRETCHED study were to: develop an understanding of predicted mechanism of change to underpin evaluation evaluate case management approaches to the care of people who call the emergency ambulance services frequently in terms of: further emergency contacts [emergency ambulance service calls, emergency department (ED) attendances, emergency hospital admissions] or death effects on other services adverse events (deaths; injuries; serious medical emergencies, police arrests) costs of intervention and care describe the epidemiology of sustained high users of emergency ambulance services understand the views and experience of patients identify challenges and opportunities using case management models, including features associated with success, and develop theories about how case management works in this population.

Authors' results and conclusions: We found no differences in intervention (n = 550) and control (n = 633) patients in the primary outcome (adjusted odds ratio: 1.159; 95% confidence interval: 0.595 to 2.255) or its components. Nearly all patients recorded at least one outcome (95.6% intervention; 94.9% control). Mortality was high (10.5% intervention; 14.1% control). Less than 25% of calls resulted in conveyance (24.3% intervention; 22.3% control). The most common reasons for calling were ‘fall’ (6.5%), ‘sick person’ (5.2%) and acute coronary syndrome (4.7%). Case management models varied highly in provision, resourcing, leadership and implementation costs. We found no differences in costs per patient of healthcare resource utilisation (adjusted difference: £243.57; 95% confidence interval: −£1972.93 to £1485.79). Service providers (n = 31) recognised a range of drivers for frequent calling, with some categories of need more amenable to case management than others. Some service users (n = 15) reported deep-seated and complex needs for which appropriate support may not have been available when needed. People who called frequently had a high risk of death and emergency healthcare utilisation at 6 months and were a heterogeneous group. Case management may work for some, but we did not find effects on emergency healthcare utilisation or mortality across the population. Natural experiment We included in analyses data on n = 1183 patients: 550 at intervention sites and 633 at control sites. There was considerable variation in numbers of patients by ambulance service and arm, particularly noticeable in the intervention arm, with over half the patients in one site. Overall, study patients were relatively elderly, with a median age of 65 years (lower quartile 45, upper quartile 81), with slightly more females (51.9%), and were predominantly white (81.7%). Just under two-thirds of patients (65.1%) lived in areas classified in the two most socioeconomically deprived quintiles, only 5.2% lived in areas classified in the least socioeconomically deprived quintile. Intervention site patients were generally younger than control site counterparts in three out of the four participating ambulance services (AS2, AS3 and AS4), and hence generally younger overall (median age: 60 years for the intervention arm; 69 years for the control arm). The proportion of female patients varied from 44.1% (AS2 intervention site) to 59.2% (AS1 intervention site), with no obvious pattern across study arms or ambulance services. Emergency ambulance service use by patients for the 6 months before inclusion in STRECHED was similar between arms. Approximately two-thirds of patients recorded at least one emergency admission (753/1183; 63.7%), and/or outpatient appointment (804/1183; 68.0%). The proportions of patients recording emergency admissions, ED attendances, elective admissions and outpatient appointments were generally similar between arms; however, the overall mean number (per patient) of emergency admissions, elective admissions and outpatient appointments were all higher in intervention sites. The proportion of patients recording at least one component of the composite primary outcome was very high and similar between study arms: 95.6% in the intervention arm; 94.9% in the control arm [odds ratio (OR) = 1.159; 95% confidence interval (CI) 0.595 to 2.256; p = 0.665]. The majority of patients made at least one further emergency ambulance service call in the 6-month follow-up; almost as many patients recorded an event in at least one other component of the composite measure. The proportion of patients that died within the 6-month follow-up period was relatively high (10.5% intervention, 14.1% control). Although mortality did not differ significantly with study arm (OR = 0.713; 95% CI 0.465 to 1.093; p = 0.121), it was strongly associated with age (p 

Authors' methods: A mixed-methods ‘natural experiment’, evaluating anonymised linked routine outcomes for intervention (‘case management’) and control (‘usual care’) patient cohorts within participating ambulance services, and qualitative data. Cohorts met criteria for ‘Frequent Callers’ designation; we assessed effects of case management within 6 months on processes, outcomes, safety and costs. The primary outcome combined indicators on mortality, emergency hospital admission, emergency department attendance and emergency ambulance call. Focus groups and interviews elicited views of service providers on acceptability, successes and challenges of case management; interviews with service users examined their experiences. Four United Kingdom ambulance services each with one intervention and one control area. Natural experiment: adults meeting criteria for ‘frequent caller’ classification by ambulance services during 2018. Service providers: service commissioners; emergency and non-acute health and social care providers. Service users: adults with experience of calling emergency ambulance services frequently. Usual care comprised within-service management, typically involving: patient and general practitioner letters; call centre flags invoking care plans; escalation to other services, including police. Intervention care comprised usual care with optional ‘case management’ referral to cross-service multidisciplinary team to review and plan care for selected patients. This retrospective study provided limited options in selecting control areas, or in meeting recruitment targets. Data quality was variable. Arranging patient interviews proved challenging. STRETCHED was designed as a mixed-methods ‘natural experiment’ evaluation based on anonymised linked routine outcomes and qualitative data in four UK ambulance services: East of England Ambulance Service, London Ambulance Service, Welsh Ambulance Service and West Midlands Ambulance Service. These services each identified where case management and usual models of care were in place in different areas (‘sites’) within its catchment area. The natural experiment design established links between exposure to care model and outcomes. Natural experiment Involving adults meeting nationally agreed criteria for classification as ‘frequent caller’ by ambulance services during 2018. The study population comprised patients that had made 5 or more emergency ambulance service calls in 1 month or 12 or more calls in 3 months, were aged 18 years or older at the time of classification as ‘frequent caller’, and resident in a study site at that time. Patients were included in the study cohort the first time they became eligible for classification as ‘frequent caller’; two ambulance services included patients already so classified at the start of 2018. Usual care comprised within-service management, typically involving: letters to patient and general practitioner (GP); call centre flags to invoke care plans, including ‘no send’ option; escalation to other services, including police action. Intervention care comprised usual care with option of referral to cross-service multidisciplinary team (MDT) to review and plan care for selected patients in a case management approach.

Authors' identified further research: This should prospectively evaluate different forms of case management; improve data collection; and include patients fully in qualitative components.

Project Status: Completed

URL for project: https://www.journalslibrary.nihr.ac.uk/programmes/hsdr/18/03/02

Year Published: 2025

URL for published report: https://www.journalslibrary.nihr.ac.uk/hsdr/PWGF6008

URL for additional information: English

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: England, United Kingdom

DOI: 10.3310/PWGF6008

Organisation Name: NIHR Health Services and Delivery Research programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk