West Midlands Renal Network
Proposed geographical boundaries for new referrals
Background
The West Midlands haemodialysis capacity plan (2004) noted that
individual dialysis units do not have a geographically discrete catchment
population. Patients frequently travel across PCT borders to distant units
to receive treatment. The figure shows the distribution of patients and their
provider units across the West Midlands. There is considerable overlap,
particularly in central Birmingham.
This overlapping of catchment areas has several disadvantages:
o Average travelling times are increased.
o Prediction of future demand for an individual provider unit is
less accurate.
o Calculation of acceptance rates by provider unit (important
for comparing performance of units) is impossible.
o When dialysis capacity is short it may be difficult to agree
which provider is responsible for taking on a new patient
living half way between two units.
The report concluded that:
Establishment of referral pathways with identified catchment
areas would overcome these problems. Catchment areas should
probably be defined by PCT boundaries to enable reconciliation
of supply and demand calculations and to simplify
administration.
This approach would have to be flexible enough to
accommodate patient choice but it is unlikely that many patients
will elect to receive treatment in a distant unit.
Further work was required to determine optimal boundaries for
catchment areas. This should include repeat demand modelling
using the new catchment areas as a denominator to ensure that
the process will not result in unsustainable shifts in activity
between providers.
Methodology
Work on defining appropriate referral areas was undertaken in collaboration
with Diane Edwards of the University of Birmingham.
Optimal referral pathways were defined in terms of the shortest travelling
times for patients. These were determined as follows:
1. The location of 8 base dialysis units, 14 satellite dialysis units and
prevalent haemodialysis patient distributions were mapped by managing
renal service provider.
2. For this exercise it was assumed that there will be an independent dialysis
unit in the Worcester area. Without this the catchment areas in the south
of the region become so elongated and distorted that analysis is
impossible. For this report the virtual Worcester unit is considered to be
part of the University Hospital.19 of the 22 dialysis units are used solely by
one renal service provider. 3 (Lichfield, Tipton & Kidderminster) serve
more than one base renal unit and were excluded from this stage of the
analysis.
3. ‘Nearest neighbour’ areas were created around each of 19 dialysis units
by geographical distance (as opposed to travel times).
4. ‘Nearest neighbour’ areas of the 19 dialysis units were aggregated to the 8
service providers creating a ‘nearest neighbour’ allocation to each service
provider.
5. The relationship between 30 minute travel time zones from each of 19
dialysis units and ‘nearest neighbour’ referral areas was considered. 30
minute travel zones for 19 dialysis units were aggregated to ‘sole user’
renal units.
The figure below illustrates the initial results of this process. From this it is
possible to allocate PCTs to service provider units. Where possible allocation
has been made at a PCT level though some PCTs straddle more than one
optimal catchment area (e.g. SW Staffordshire). In these instances it was
necessary to split the PCT and referral pathways for individual GP practices
will need to be defined.
Once PCTs were allocated to service provider units the impact of this on
projected activity for each provider was determined using the 2003-4 and
2004-5 new referral data provided by units for the 2005 revision of the West
Midlands 5 year haemodialysis capacity plan.
Results
Table 1 show the optimal allocation of PCTs to service provider units based
upon travel times and geographical distance. The extreme SE of Shropshire
County PCT is clearly nearer to Wordsley dialysis unit that to Shrewsbury.
Similarly SW Staffordshire crosses the ideal catchment of North Staffordshire,
Wordsley and Wolverhampton dialysis units. It would be illogical to allocate
these PCTs to a single provider unit. The exact position of the boundary still
needs to be determined but for this analysis it is assumed that new patients
from SW Staffordshire will be shared equally between three units and one
tenth of the Shropshire County patients will go to Wordsley.
Table 1
Provider Trust
PCT
UHB
Heart of Birmingham PCT
+ Hereford & Worcester Oldbury and Smethwick PCT
South Birmingham PCT
Redditch and Bromsgrove PCT
South Worcestershire PCT
Herefordshire PCT
Heartlands
Eastern Birmingham PCT
North Birmingham PCT
Solihull PCT
Burntwood Lichfield and Tamworth PCT
Wolverhampton
Wolverhampton City PCT
Walsall PCT
Wednesbury and West Bromwich PCT
Cannock Chase PCT
SW Staffordshire PCT (central part)
Shrewsbury
Shropshire County PCT (except extreme SE)
Telford and Wrekin PCT
Coventry
Coventry PCT
North Warwickshire PCT
South Warwickshire PCT
Rugby PCT
Wordsley
Wyre Forrest PCT
Dudley Beacon and Castle PCT
Dudley South PCT
Rowley Regis and Tipton PCT
Shropshire County PCT (extreme SE)
SW Staffordshire PCT (Southern part)
North Staffordshire
East Staffs PCT
Newcastle –under-Lyme PCT
North Stoke PCT
South Stoke PCT
SW Staffordshire PCT (northern part)
Staffordshire Moorlands PCT
These proposed referral pathways may not correspond to current practice –
particularly in central Birmingham. Thus it is necessary to attempt to predict
what effect the adoption of these proposals will have on the number of
patients referred to each unit.
Table 2 shows the actual numbers of patients referred to each of the provider
units in 2003-4 and 2004-5 and the annual numbers which would have been
referred if the proposed geographical referral pathways had been in place.
Table 2
Numbers of new patients each year for provider trusts
Provider Trust
Actual
Actual
2003-4
2004-5
Annual
predicted
with new
referral
pathways
190
UHB
+ Hereford & Worcester
Heartlands
234
201
111
108
98
Wolverhampton
86
118
120
Shrewsbury
39
43
47
Coventry
75
91
87
Wordsley
39
38
58
North Staffordshire
68
66
60
These data show that for the majority of providers adoption of the proposed
referral boundaries will have no appreciable effect on activity levels. The
exception is Wordsley which would see an increase of approximately 20
patients per annum. While this number is small in real terms, it represents a
50% increase in new patients for the unit.
As the recommendations only apply to new patients any change in overall
workload for the units would happen slowly over several years. As we move to
PbR this changes in activity will be followed automatically by appropriate
changes in revenue.
There is a small reduction in activity predicted for both of the central
Birmingham units. The proposed development of a new satellite unit in Balsal
Heath which will be linked to Birmingham Heartlands Hospital may require
revision of the border between the Heart of Birmingham and Eastern
Birmingham PCTs. This would further reduce UHB activity and increase
Birmingham Heartlands activity.
Recommendations
This document should be subject to wide consultation before implementation
is considered. Commissioners and providers should examine the detail of the
proposals for their area of responsibility to ensure that they make sense at a
local level. Comments should be returned to Steve Smith by the end of
September 2005. The final version of this document will be presented for
approval at the November network meeting.
These recommendations are intended for new referrals. Renal patients
already under treatment with a service provider are usually reluctant to
change units. It would be inappropriate to force existing patients to transfer to
a different service provider.
Patient choice remains important and so these recommendations will not be
binding. In most instances it would not be in the patients’ best interest to
choose to go to a geographically distant unit so exceptions are likely to be
uncommon.
Units should keep a record of all new patients that they take on for dialysis
from outside their recommended catchment area. This information should be
reported to the network on an annual basis and used to inform future revisions
of the boundaries.
There will be no need for significant transfer of resources between units in the
short term to implement these recommendations.
Steve Smith
West Midlands Renal Network
August 2005