1. Mathematics and Healthcare: Saving Lives and Reducing Costs
Submitting Institution
Cardiff UniversityUnit of Assessment
Mathematical SciencesSummary Impact Type
HealthResearch Subject Area(s)
Mathematical Sciences: Applied Mathematics, Statistics
Economics: Applied Economics
Summary of the impact
Research conducted at the School of Mathematics at Cardiff University has
engineered lifesaving, improvements to UK healthcare systems. New
mathematical models, accounting for the complexity and diversity of the
health system, have been created and applied in a variety of contexts to
markedly enhance the efficiency and effectiveness of a wide range of
healthcare services — at policy, commissioning and operational levels. The
extensive benefits include:
- Reducing the mortality of trauma patients across South London by 54%
(equating to 0.7 additional survivors out of every 100 patients for the
period 2010-2012, rising to 4.2 in 2013)
- Reducing the mortality of stroke patients across South London by 60%
through the creation of a new Stroke Unit, based on the research
findings (the services were rated as the best in the country by the
National Sentinel Audit 2010 organised by the Royal College of
Physicians).
- Realising net efficiency gains of £1.6m per year in the emergency
department at University Hospital of Wales;
- Provision of hospital capacity planning tools in use across the UK
This work has been disseminated nationally and internationally, in the
media and at a range of events designed to engage the public with
Mathematics. Therefore the impacts claimed in this case study are health,
economic benefits and public engagement.
Underpinning research
Modelling health systems requires the development of suitable
mathematical models that are able to account for dynamic processes,
stochastic conditions, and high levels of complexity. This has been
achieved by the Operational Research (OR) group at Cardiff University from
1993-2012. The range of methodologies employed may be categorised as
follows:
Queueing Systems (Griffiths, Harper, Williams and
Knight)
Patient movements through healthcare systems (care-pathways) can be
represented by flows through networks of queues constrained by available
resources. Previous contributions in queueing theory have focussed on bulk
service queues and time-dependent queueing models. Theoretical work has
made significant progress with the transient solution of queueing systems
and the time-dependent nature of queues including multi-server queues with
priority (3.1) The stochastic nature of demand on acute hospital services
and the expected consequences on resource requirements, taking into
consideration both intra week and monthly seasonality, required the
development of a complex simulation packages by members of the OR group.
These packages enable simulation studies to be performed quickly and
efficiently, without highly specialised expertise and extensive
configuration times (3.2).
Exploiting known information on patient characteristics, such as age,
gender, socio-economic status etc, can allow for predictions on individual
patient resource needs and outcomes. Novel work on developing a discrete
conditional phase-type framework demonstrated the benefits of Coxian
phase-type distributions interfaced with classification tree algorithms.
Underpinning work also embedded Coxian phase-type service time fits within
M/PH/c/NPRT priority queueing and simulation
models (3.3).
Behavioural Modelling (
Harper, Griffiths, Williams and
Knight)
It is well observed that individual behaviour can affect the efficiency
of queueing systems. To address such issues, using theoretical insights
from routing game theory, algorithmic approaches for obtaining the price
of anarchy were proposed. Theoretical results were obtained as to the
demand and worth of service. It was shown that in a public service system,
with an adequate capacity to provide the perceived worth of service, a
high price of anarchy is to be expected (3.4).
Recognising that the structure of social networks also play an important
role in the dynamics of healthcare processes, research explored small
world principles to capture disease propagation dynamics as well as agent
based simulation investigations into the consequential effects of social
networks and behavioural (3.5). For the first time in the literature,
formal psychological models (such as theory of planned behaviour) were
integrated with physiological parameters within the same clinical model to
provide greater understanding of the importance of human behaviour in
healthcare simulations.
Facility Location (Harper and Knight)
The research considered the development of mathematical models for
locating facilities, including those within hierarchical systems. The
novelty and contribution of this work was to incorporate both equity and
efficiency parameters into proposed classes of optimisation model, thus
permitting decision making when considering both `fair' and `efficient'
locations. Other research proposed new mathematical formulations for
locating emergency medical services that incorporate the survival of
heterogeneous patient classes. An extended iterated method of solving the
model was developed that uniquely takes in to account the reactive nature
of the stochastic conditions (3.6).
Key staff contributing to the research: Professor Jeff Griffiths
(academic staff 1964-), Professor Paul Harper (academic staff 2007-), Dr
Janet Williams (academic staff 1988-2013) and Dr Vincent Knight (research
associate 2009-2011, academic staff 2011-).
References to the research
3.1. Griffiths JD, Leonenko G and Williams JE (2006), "The
Transient Solution to M/Ek/1 Queue". Operations Research Letters,
34(3): 349-354.
http://dx.doi.org/10.1016/j.orl.2005.05.010
Copy held by HEI, available on request.
3.2. Griffiths JD, Knight VA and Komenda I (2013), "Bed
Management in a Critical Care Unit". IMA Journal of Management
Mathematics. 24(2): 137-153.
http://dx.doi.org/10.1093/imaman/dpr028
Copy held by HEI, available on request.
3.3. Harper PR, Knight VA and Marshall AH (2012), "Discrete
Conditional Phase-type Models Utilising Classification Trees: Application
to Modelling Health Service Capacities". European Journal of
Operational Research. 219(3): 522-530.
http://dx.doi.org/10.1016/j.ejor.2011.10.035
Copy held by HEI, available on request.
3.5. Vieira IT, Cheng RCH, Harper PR and de Senna V
(2010), "Small World Network Models of the Dynamics of HIV Infection". Annals
of Operational Research. 178: 173-200.
http://dx.doi.org/10.1007/s10479-009-0571-y
Copy held by HEI, available on request.
3.6. Knight VA, Harper PR and Smith L (2012), "Ambulance
Allocation for Maximal Survival with Heterogeneous Outcome Measures". OMEGA:
The International Journal of Management Science. 40(6): 918-926. http://dx.doi.org/10.1016/j.omega.2012.02.003
Copy held by HEI, available on request.
Details of the impact
The mathematical models developed by the OR group at Cardiff University
have been applied to a wide range of healthcare services, in a variety of
hospitals, across the UK. The impacts directly arising from the research
are highly significant and include:
Health Benefits
The research has been used in a major new trauma centre that opened in
2010, at St George's Hospital in London (a capital investment of £3.6m).
The models were used to create service level agreements (annual capacity
planning) with commissioners over several years and, importantly, informed
the required patient-flows and resourcing levels for the centre. This
enabled patient waiting time to be reduced and better levels of patient
care achieved through improved resource management and greater efficiency.
The result has been an observed increase in survival rates of 54%. Jen
Goddard, Business Analyst at St. George's Hospital, stated, "The research
and tools that Cardiff University provided have been extremely useful to
St George's, enabling us to understand and model our data and use it to
significantly improve patient care and resource management. Mortality
rates have fallen as a consequence of the implementation of the Major
Trauma Centre and the Hyper Acute Stroke Unit." (5.1)
The models were similarly utilised by a new hyper-acute stroke unit
covering the South London area. The new unit and stoke care service were
rated as the best in the country by the National Sentinel Audit 2010
organised by the Royal College of Physicians. The outcomes were again
lifesaving; significantly lowering risk-adjusted mortality for stroke
patients to 60%. This is verified by data comparing mortality rates pre
and post the implementation of the research (provided by Jen Goddard, St.
George's Hospital). (5.1)
Patient care and hospital resources have also been significantly
improved, through the work of the OR team, at a major neurological
rehabilitation hospital in South Wales (Rookwood Hospital, Cardiff).
Previously the complex scheduling of inpatient physiotherapy sessions was
undertaken manually which was time consuming and amounted to a clinician
spending one day per week assembling the following week's timetable. The
research enabled the scheduling process to be automated; the computerised
new system has been implemented since January 2011. It produces a vastly
enhanced schedule within minutes, enabling clinicians to devote more time
to assessing patients' needs and delivering medical care. Jakko Brouwers,
Senior Service Improvement Programme Manager at the Hospital commented,
"Your research work with our Department of Specialist Physiotherapy and
Rehabilitation at Rookwood Hospital has had a huge impact on how we
utilise our resources. ... The automated computer scheduling creates a
fairer system for patients as it takes into account what treatment the
patient received the previous week." (5.2)
The work at Rookwood Hospital also included a detailed queueing analysis
of their patient admission and discharge process, with particular emphasis
on tailoring physiotherapy treatment to the needs of the patient. This
optimised the length of stay in the unit and provided improved quality of
life for patients. Jakko Brouwers added, "The service modelling work has
been a real asset in that it has opened the eyes of the operational
service manager to the issues regarding patient flow. These insights are
now used on a regular basis in waiting list management and admissions
meetings." (5.2)
The research has been particularly significant to the Welsh Ambulance
Service Trust (WAST). Like all Emergency Medical Services WAST is under
increasing pressure to provide wide geographical coverage and improve
performance to meet Government set response times. The work at Cardiff
University has helped WAST by forecasting 999 calls by category of call
and providing valuable evidence to confirm the importance of ambulance
allocations based on patient outcomes for different conditions (using
survival probabilities) as opposed to only those based on hard time
targets (e.g. 8 minute response). This means that extra lives can be
saved. Researchers at Cardiff University have quantified the relationship
between overall service performance and changes to durations in each
phase. Critically, the findings show that reducing the time of the patient
handover from ambulance to the emergency department at hospitals makes the
biggest impact on overall WAST performance. Richard Whitfield, the
Research and Development Manager at WAST stated that "the work is an
extremely relevant contribution to implementing policy and procedural
changes at WAST." (5.3)
Financial Benefits
The research entailed modelling the Emergency Unit (EU) at the University
Hospital of Wales (UHW). This enabled the hospital to examine the
reconfiguration of services and identify problems in the system.
Subsequently major changes were implemented, based on the results of the
research, leading to a huge alteration in patient flows in the EU. This
meant that the hospital was able to reduce staffing levels and the number
of trolleys by 43%, amounting to a net efficiency gain of approximately
£1.6m. Andrew Nelson, Director of Acute Services, Cardiff and Vale
University Health Board, commented, "The modelling work provided by the
Maths school has been the basis of our plans for the current major
re-design and refurbishment of the Accident and Emergency Department at
the University Hospital of Wales. This is the second major change
resulting from the work undertaken by the maths school to improve our
knowledge of demand and capacity within the department and how we can best
equip the department to improve performance and overall cost
effectiveness". (5.4)
The models were used to evaluate the impact of the South Wales
Development Programme, leading to a £4.2 million investment in system wide
capacity. This has allowed Cardiff and Vale University Health Board to
better align resources with the needs of patients. Moreover, it has formed
the basis of a successful joint bid with Social Services for a £2.5
million invest-to-save scheme with the Welsh Government to improve
non-emergency transport services for hospital patients. (5.4)
Public Engagement
The research has been widely disseminated in the UK and overseas and has
led to a significant level of public engagement. Examples of this include
a series of four radio programmes that were aired on BBC Radio Wales
(2010) as part of its weekly programme called `Science Cafe'. Seminars
have been given in America at Princeton University, New Jersey; Columbia
University, New York; Baylor University, Texas. The audiences comprised of
a mixture of nonspecialists, teachers and students. Professor Griffiths
has also spoken at the Cardiff Scientific Society, which seeks to extend
interest in the application of Science to everyday life. His latest talk
in October 2012 was entitled "Some Queues I've enjoyed". Professor Harper
has also given a wide range of public talks including speaking at the
Cardiff University's Innovation Network event in April 2013. This was
attended by 70 delegates, including health care professionals, who scored
the event 4.2 out of a possible 5. (5.5)
Outreach activities, where the healthcare modelling research has heavily
featured, have involved over 500 school children. Regular sessions are
given, for example, at the Monmouth Science Initiative
(www.monmouth-science.co.uk). (5.6) Online resources, concerning
healthcare modelling topics, have also been created for teachers and
students, and are also part of national initiatives such as that by the OR
Society (www.learnaboutor.co.uk). (5.7)
Sources to corroborate the impact
5.1 Business Analyst, Strategy, St George's Healthcare Trust,
London. Corroborates the use and impact of the models at St George's
Hospital.
5.2 Senior Service Improvement Programme Manager, Rockwood
Hospital. Corroborates the use and impact of the models at Rockwood
Hospital.
5.3 Clinical R&D Manager, Welsh Ambulance Service NHS Trust. Corroborates
the value of the research to WAST.
5.4 Director of Acute Services, Cardiff and Vale University Health
Board. Corroborates the use and impact of the models at the University
Hospital of Wales.
5.5
http://www.innovation-network.org.uk/events/innovation-in-healthcare-wed-17-apr-2013.aspx
Provides an example of the public talks given as a result of the
research.
5.6 http://www.monmouth-science.co.uk/programme/physics/
Confirms Cardiff's involvement in outreach activities, stemming from
the research.
5.7 http://www.profpaulharper.com/home/school-outreach
Confirms that online resources for teachers have been developed from
the research.