Overview of study and intervention characteristics and implementation outcomes associated with diversion implementation
| Author ID Study Design/methodological quality | Diversion intervention (I) features | Comparison (C) features | Geographic setting and scope | Study participants | Implementation | ||||||
| Sample size | Target age (sample mean or median) | Target complaints | % participants eligible | % participants diverted * | % participant adherence | % participants refused diversion | Initial ED attendance | ||||
| Pre-hospital diversion | |||||||||||
| Dale (2003)18 Controlled clinical trial High risk of bias | A nurse or paramedic assessed 999 calls as to whether or not to dispatch ambulance. If caller triaged as not requiring an ambulance, they were offered advice and asked whether they still wished an ambulance to attend. Ambulance was not cancelled without consent of caller | Usual ambulance response with no telephone assessment/advice | England Ambulance service sites covering the whole of Greater London, Birmingham, Coventry, the Black Country and South Staffordshire; total population of about 10 million | I: 635 C: 611 | All ages (I: mean 44 years, C: mean 49 years) | Non-serious concerns | 51.9% (n=330/635) | 36.1% (n=119/330) | NR | 62.4% (n=206/330) | RR†0.76 (95% CI 0.69 to 0.84) |
| Krumperman (2015)24 Observational cohort Moderate quality | Low-acuity calls to a 911 call centre were diverted to a nurse call centre. A nurse used a protocol to provide advice and/or refer caller to their PCP or urgent care centre | Paramedics decided whether concern could be treated at the scene and/or referred to a PCP | USA. Ambulance service sites covering a rural and urban area; exact setting and population not reported | I: 216 C: 374 | All ages (NR) | Low-acuity concerns | NR | NR | 95% (n=205/216) | NR | NR |
| Mason (2007)11 Mason (2008)15 Dixon (2009)14 Cluster RCT High risk of bias | Paramedic practitioner travelled with the ambulance and was trained to assess and treat low-acuity complaints at the scene | Usual ambulance response, including EMS crew assessment and transport to the ED | England Ambulance service sites covering Sheffield. | I: 1549 C: 1469 | ≥60 years (mean 83 years) | Minor injury or illness | NR | Mason 200711 70.4% (n=1090/1549) | NR | NR | NR |
| Mason (2012)19 Quasi-experimental trial Low quality | Emergency care physicians working as a single responder to ambulance service 999 calls who assesses the patients and either discharges them at the scene or refers to the most appropriate care practitioner | Standard paramedic/technician ambulance responding to ambulance service 999 calls | England & Scotland All NHS trusts employing emergency care physicians in England and Scotland were invited to participate. ’Control’ trust sites that did not employ emergency care physicians but were within the same or in a neighbouring county and offered the same service configurations as intervention trusts were selected to participate | I: 593 C: 514 | Unclear (I: mean 69 years, C: mean 63 years) | Not specified. Emergency or urgent complaints that were eligible to be seen by the emergency care physicians | NR | 43.3% (n=257/593) | NR | NR | NR |
| Ross (2013)25 Observational cohort Moderate quality | Paramedic evaluation and transport to a detoxification facility with limited medical care on a 24-hour, 7-day per week basis | Transport to the ED | USA El Paso County ambulance service agencies covering the greater Colorado Springs metropolitan area; total population of about 370,000 | I: 138 C: 580 | >18 years (I: median 46 years, C: median 43 years)‡ | Alcohol intoxication without any significant acute illnesses or injuries | 19.2% (n=138/718) | 92% (n=127/138) | NR | NR | NR |
| Snooks (2004)16 Cluster RCT High risk of bias | Ambulance crews transported patients who met specific criteria to a minor injury unit | Transport to the ED | England Five ambulance stations in the London and Surrey ambulance services | I: 409 C: 425 | Unclear§ (NR) | Minor injuries, but not illnesses | NR | 10% (n=41/409) | NR | NR | RR†0.96 (95% CI 0.89 to 1.04) |
| Snooks (2004)22 Observational cohort Moderate quality | Ambulance crews used protocols to treat patients who fell within a list of dispatch criteria at home (treat and release) | Transport to the ED | England Two ambulance stations in West London | I: 251 C: 537 | Unclear (I: mean 54 years, C: mean 47 years) | Non-serious injuries or illnesses | NR | 37.1% (n=93/251) | 40.2% (n=101/251) | NR | NR |
| Snooks (2014)13 Cluster RCT High risk of bias | Computerised clinical decision support tool for paramedics to use to decide whether to take patients who had fallen to the ED or leave at home with referral to a community-based falls service | Transport to the ED | Wales Recruited patients from two UK study sites. Paramedics were eligible to participate in the trial if they worked at any of 13 ambulance stations with a falls referral pathway in place | I: 436 C: 343 | >65 years (I: median 83 years, C: median 82 years) | Falls | NR | 42% (n=183/436) | NR | NR | RR†0.94 (95% CI 0.82 to 1.09) |
| Snooks (2017)12 Cluster RCT High risk of bias | Clinical protocol used by paramedics for the care of older people who have fallen to assess and refer them to a community-based falls service | Transport to the ED | England and Wales Three ambulance services in England and Wales in which a falls prevention service was available, but no services in place for paramedics to make referrals from the scene of emergency service call attendances | I: 2420 C: 2284 | >65 years (I: mean 82.54 years, C: mean 82.14 years) | Falls | 90.4% (n=2161/2391) | 8.4% (n=204/2420) | NR | NR | RR†1.04 (95% CI 1.00 to 1.09) aOR¶ 1.08 (95% CI 0.96 to 1.22) |
| ED-based diversion | |||||||||||
| Doran (2013)20 Quasi-experimental trial Low quality | Research specialist and triage nurse identified eligible patients to be escorted from the ED waiting room to the primary care clinic | Usual ED care | USA Adult academic ED serving 100 000 patients treated yearly | I: 662 C: 191 | ≥23 years (I: mean 47.3 years, control: mean 46.3 years) | Any | 25.7% (n=1404/5462) | 85% (n=563/662) | 93.4% (n=526/563) | 15% (n=99/662) | NR |
| Ellbrant (2015)23 Observational cohort Moderate quality | PED nurse determined whether patients would be sent home, referred for other ED care or admitted | PED physician who determined whether patients would be sent home, referred for other ED care or admitted | Sweden Academic hospital in Malmö, Sweden, serving approximately 400 000 urban people | I: 344 C: 713 | 0–17 years (NR) | Any | 32.5% (n=344/1057) | 84.3% (n=290/344) | NR | NR | NR |
| Washington (2002)17 RCT Unclear risk of bias | Triage nurses used standardised criteria to identify patients who would be safe for deferred care at a non-emergency setting at a later date | Usual ED care | USA Academic level 1 hospital in Los Angeles County, California, with 91 000 visits annually | I: 75 C: 81 | >18 years (I: mean 41 years , C: mean 42 years) | Abdominal pain, musculoskeletal symptoms, or respiratory infection | 35.7% (n=421/1176) | 100% (n=75/75) | 96% (n=71/74) | 48% (n=143/299) | NR |
| Washington (2000)21 Observational cohort Moderate quality | USA Tertiary care medical centre in Los Angeles, California, with approximately 30 000 unscheduled walk-in visits | I: 226 C: 961 | >18 years (mean 53 years of those patients screened n = 1187) | 19% (n=226/1187) | 68.1% (n=154/226) | 90.3% (n=139/154) | NR | NR | |||
*Those participants assigned to receive diversion and were actually diverted from the ED.
†Unadjusted RR.
‡Median age reported.
§The study did include paediatric patients <5 years of age, but an upper age limit was not specified.
¶As well as indicators for group, site and their interaction, covariates adjusted for included age and its square, distance to ED, recruitment point, seasonality, biological sex and whether or not the index call was made out of GP hours.
a, adjusted; ED, emergency department; GP, general practitioner; NA, not available; NR, not reported; PCP, primary care physician; PED, paediatric emergency department; RCT, randomised controlled trial; RR, relative risk.