NHS-accident-emergency-travel-time-map

Travel Time Map to NHS A&E  Services

The ability to access emergency healthcare services within easy reach is seen as a key marker by local communities of investment and engagement by the NHS and ultimately their political masters.  Indeed, one only needs to watch the public outcry (and support from politicians from all parties) when the NHS wants to close or reconfigure local emergency services to see how much these services are valued.  Despite this there is little published information concerning travel times to emergency services within Scotland.   This work publishes, for the first time, 30 minute car travel time areas for Scotland to the nearest emergency and accident services and quantifies the impact in terms of the population.

Scotland has 30 hospitals with Accident and Emergency Departments (A&E) located in all the major towns and cities.  These are augmented by 33 Minor Injury units, frequently located within local or cottage hospitals which fill gaps in the coverage of the primary A&E departments.  Travel time to A&E services matter since a high proportion of emergency admissions to hospital for serious and life-threatening conditions is via A&E departments.  Thus increased travel time for serious conditions increases the likelihood of a poorer outcome for the patient.

The Scotland map (Fig 1) shows areas (pink shading) where the drive time to the nearest A&E department (blue dots) is less than 30 minutes.  As a result of clustering of hospital units the 30 minute drive time zones (DTZ-30) overlap to give a contiguous area which extends across the central belt, north east up to Angus, south east into the Borders and south west to Ayrshire. Other areas tend to spread out from a single hospital service.

When Minor Injury Unit (MIU) 30 minute drive times are included in the analysis the area of the 30 minute zone expands considerably  (Fig 2. Pink shading). This is due to the fact that with the exception of Glasgow and Edinburgh the majority of MIUs are well separated from major general hospitals and often located in strategic outposts where local and or cottage hospitals provide a rage of services within local communities. Many of the services are MIUs located in the larger islands and based at cottage hospitals. In the central belt the 30 minute zone extends north east past Arbroath and Forfar, south west down to Wigtownshire and south east to cover large parts of the Borders.

Population Impact of Drive Time to Hospital A&E Department

Approximately 88% of Scotland’s population live within a 30 minute drive time (DTZ-30) of a general hospital A&E department (Table1, Fig 1).   From the map below it is also evident that vast areas of Scotland lie outside of a DTZ-30, however, because these areas on the whole correspond to more rural areas with few large towns these regions the population residing in these areas is limited to 12% of the population.  For details of the methodology please see below.

Although not directly comparable in terms of methodology a study in England showed that 9% of the population traveled over 20 km for emergency admissions (the vast majority of which is via A&E units) and 3% traveled over 30 km.  Thus given the more remote nature of Scotland’s geography the Scottish figures stack up favourably compared to the travel distances (thus times) in England which is more densely populated (see https://www.nuffieldtrust.org.uk/files/2018-10/1540325897_qualitywatch-distance-emergency-care.pdf, page 16).

Table 1: Population within 30 minute travel time zone to A&E department

Category Population Percent
 within 30 minute drive time  4,787,612  88%
 greater than 30 minute drive time  637,188  12%

 

Fig 1:  Travel time overlays showing areas within 30 minutes travel time by car to the nearest Accident and Emergency Department
30 minute travel zones: pink shading, A&E departments blue dots.
Click on blue dot for pop-up with facility details.


Population Impact of Drive Time to All A&E Services (includes MIU)

The impact of the addition 33 MIUs to the travel time zone calculations results in a large expansion in the area of the zones covered by a 30 minute drive time.  This leads to an additional 309,280 people living within 30 minutes of an A&E or MIU service with 4% of the population live within a A&E + MIU DTZ-30 area.

Table 2: Population within 30 minute travel time zone to A&E or MIU service

 Category  Population  Percentage
 within 30 minute drive time  5,096,900  94%
 greater than 30 minute drive time  327,900  6%

 

Fig 2:  Travel time overlays showing areas within 30 minutes travel time by car to the nearest A&E or MIU service
30 minute travel zones, pink shading: A&E departments, blue dots: MIU service red dots.
Click on blue/red dot for pop-up with facility details.

Air Ambulances

Much of Scotland consists of remote mountains,  uplands and islands with local populations and visitors poorly connected to health service providers.  In recognition of this, Scotland has the only government funded air ambulance service in the UK which provides additional means for faster access to hospital-based emergency services.

Scottish Air Ambulance Service
The government funded Scottish Air Ambulance Service comprises two air ambulance helicopters and two fixed wing aircraft.  The helicopter service provides emergency response cover and the fixed wing aircraft provides hospital transfer and transport for patients to and from remote areas and islands.  Helicopters are based in Glasgow and Inverness and the fixed wing aircraft from Aberdeen.

Scottish Charity Air Ambulance
Scotland’s Charity Air Ambulance service has two air ambulance helicopters providing emergency response services based in Aberdeen and Perth.

 

Methods

Data
Data correct as of 20-01-2022

Hospitals with Accident and  Emergency departments or Minor Injuries Units were obtained by analysis of information published by Public Health Scotland.  Latitude Longitude coordinates for each were obtained by geocoding from the address using Nominatum’s utilities https://nominatim.org/.

Travel Time
Travel time polygons (isocrones) were created for each A&E or MIU on QGIS mapping software using the Openroute Service plugin for QGIS (https://openrouteservice.org/dev/#/signup).  Overlapping isocrones were joined to yield 15 areas across Scotland with a travel time to A&E or MIU by car of 30 minutes or less (DTZ30).  These were exported as shapefiles for further analysis.  Maps were produced using Python3 and Folium.

Population Estimates
Population estimates were made by using SIMD 2020 datazone population information. In order to  obtain population estimates each of the 6976 SIMD datazones (SIMDDZ) were evaluated for overlap with each of the 15 DTZ30 zones.  This analysis was carried out using Python3 and the Shapely modules.  Datazones were categorised into three zones: those contained wholly within one of the fifteen 30 minute drive time areas, those entirely outside of any DTZ30 and those zones which partially overlap with DTZ30 zones.

For SIMDDZs that overlap with the DTZ30 the percentage area of overlap was calculated (using Python as above) and the datazone population distributed pro-rata into a population living within DTZ30 and a population outwith DTZ30.

 

NHS-accident-emergency-travel-time-map

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