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Age and Ageing 2009 38(1):27-32; doi:10.1093/ageing/afn281
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© The Author 2009. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

Cost of stroke in the United Kingdom

Ömer Saka1, Alistair McGuire1,2 and Charles Wolfe1,3

1 King's College London, Division of Health and Social Care Research, London SE1 3QD, UK
2 LSE Health and Social Care, London School of Economics and Political Science, London WC2A 2AE, UK
3 National Institute for Health Research (NIHR), Biomedical Research Centre, Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK

Address correspondence to: Ö. Saka. Tel: (+44) 207 848 6629; Fax: (+44) 207 848 6620. Email: omer.saka{at}kcl.ac.uk


   Abstract
Top
 Abstract
Introduction
 Methods
 Results
 Discussion
 Key points
 Funding
 Supplementary Data
 References
 
Introduction: this study aims to quantify the annual cost of illness of stroke to the UK economy.

Methods: we estimate the cost of stroke from a societal perspective. Direct care costs include diagnosis, inpatient care and outpatient care. Income loss and social benefit payments to stroke patients are accounted for in the indirect cost calculations. Data from South London Stroke Register and a number of other national sources are used. Sensitivity analysis was carried out to account for the variability in the data used.

Results: the treatment of and productivity loss arising from stroke results in total societal costs of £8.9 billion a year, with treatment costs accounting for approximately 5% of total UK NHS costs. Direct care accounts for approximately 50% of the total, informal care costs 27% and the indirect costs 24%. Sensitivity analysis did not alter the estimate of total costs significantly for most of the variables except using of differing prevalence rates.

Conclusions: stroke incurs considerable societal costs. Our calculations show a high sensitivity to the underlying prevalence rates used. The findings highlight a need for further economic evaluations to ensure that there is an efficient use of resources devoted to the treatment of this disease.

Keywords: stroke, cost of illness, health economics, elderly


   Introduction
Top
 Abstract
 Introduction
Methods
 Results
 Discussion
 Key points
 Funding
 Supplementary Data
 References
 
Stroke is the second most common cause of death and the leading cause of disability in Europe [1]. In addition to mortality, long-term morbidity is also a significant problem leaving significant numbers with moderate or severe disabilities who are then dependent on others to carry out daily activities.

Cost of illness (COI) analysis is the main method of providing an overall view on the economic impact of a disease [2]. Such studies have been used to set priorities for health care policies and describe resource allocations for various diseases. The aim of this COI paper is to quantify resource use and indirect costs attributable to stroke in the UK. With the rapid spread of new interventions in stroke care and at a point when the specific priorities of the UK National Health Service (NHS) are changing, it is timely to examine the burden of stroke within the UK.


   Methods
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 Abstract
 Introduction
 Methods
Results
 Discussion
 Key points
 Funding
 Supplementary Data
 References
 
This study adopts a bottom-up approach [3] in calculating the treatment resources attributable to stroke as gained from the South London Stroke Register (SLSR) [4]. Individual patient-level data from the SLSR were used as the basis of the bottom-up calculations. The SLSR is a population-based register, initiated in 1995, which currently consists of over 3,000 patients living in a specific geographical locality (South London). Patients enter the register if they are recorded to have suffered an incident stroke. Stroke is defined in the SLRS in a manner consistent with the International Classification for Diseases 10th revision—ICD10 codes I60–66 [5]. This is the definition adopted in this study also.

Prevalence and incidence
Crude stroke incidence per 1,000 population in different studies ranged from 1.33 (South London) to 1.58 (East Lancashire) in the UK [6, 7, 8]. An incidence rate of 1.33 based on the South London Stroke Register, which although conservative is accurate, was used for the primary calculations in this study [6]. Prevalence was based on the data from O’Mahony et al. [9]. The number of recurrent strokes following an incident event was estimated to be one-third of the incident stroke cases [10] and the direct treatment costs of a recurrent stroke assumed to be the same as the first-ever stroke. Population figures are obtained from the Office for National Statistics (ONS) [11]. (Please see the table in Appendix 1, available on Age and Ageing online.)

Estimation of direct formal care costs
The cost of an inpatient stay was calculated using the average length of stay for stroke as documented by the SLSR for patients admitted during 2005 multiplied by the per diem cost of hospital stay. The per diem cost of inpatient stays included, cost of hospital bed (including nursing services) and the cost of physicians and therapists time. The hourly costs of specialists were calculated using the salary schedules of specialists obtained from the stroke unit at Guy's & St. Thomas’ NHS Foundation Trust as well as the per day cost of hospital stay (including nursing services) [12]. The amount of time spent by physicians, physiotherapists, occupational therapists and speech and language therapists per patient per diem is taken from De Wit et al. [13].

In addition, inpatient administration of thrombolysis was calculated separately as the SLSR does not have adequate records on thrombolysis. An estimate of the direct cost of thrombolysis was based on an earlier study of the percentage of stroke patients who receive thrombolysis, estimated to be 1% of the total admissions [14]. Unit costs of thrombolysis were also taken from the same study. (Please see the additional text in Appendix 2, available on Age and Ageing online.) The total direct treatment costs for inpatient care, diagnostic visits and tests and surgical treatment were estimated by multiplying the calculated number of incident stroke cases and the recurrent cases in the UK with the relevant direct treatment costs.

Based on SLSR records, the frequency of outpatient visits was assumed to be that over the year each patient, after being discharged from hospital, had two visits to a stroke specialist clinic. It was also assumed that all individuals had one visit to a GP after being discharged. The unit cost of a stroke outpatient clinic was taken from the Department of Health Payment by Results tariff [15]. The unit cost of a GP visit is taken from the PSSRU [16].

For drug costs the SLSR records all usage. For most drugs, the identification of the actual drug was taken from the SLRS and the relevant dosage and frequency of use were applied. The relevant unit cost taken from the British National Formulary (BNF) 2004 was then used to arrive at the total drug cost per patient for these drugs [17]. As different hypertension drugs clusters (i.e. β-blockers, ACE inhibitors, etc.) include various different types of drugs for both patented and generic drugs, with different costs, SLSR data were used to identify the most commonly used drug in each drug cluster to use as the representative treatment drug therapy. The subsequent dosage and daily frequency of use were taken from the SLRS. The relevant unit cost, taken from the BNF 2004, was then applied. The same methodology was also used to obtain the drug cost for cholesterol-lowering drugs.

SLSR records discharge destination as home, nursing home, sheltered home, residential home and long-term hospital. Using these data, Grieve et al. identify the mean length of stay across the whole SLSR population in a nursing home, residential home or a sheltered home [18]. Unit costs of stay for these various chronic care institutions were obtained from PSSRU [16]. The total cost was based on these figures.

Estimation of direct informal care costs
Time spent by the carers of disabled stroke patients was calculated. Carer costs were defined for two groups; patients attended by family members/friends and patients attended by professional carers not employed by the NHS (e.g. home help). SLSR collects cross-sectional data on the assistance needs of patients. If patients answered yes to the question ‘Did you need assistance in the past 2 weeks?’, then they were assumed to be in need of assistance for daily activities for the whole period. A supplementary question asked whether they paid for such assistance and if they answered yes, it was assumed that a private daily carer was recruited. The national mean hourly wage rate was used to cost home help [19]. The unit cost for the care provided by family members was obtained from Liu et al. [20] as the hourly wage for over 65 years of age, unemployed or economically inactive carers. These unit costs were multiplied by the service use data from SLSR.

Estimation of indirect costs
The indirect costs resulting from premature death from stroke were based on data obtained from the ONS. Five-year age bands identifying the numbers of deaths from stroke in each band were obtained. The patients younger than 65 years of age were assumed to be economically active. The loss of earnings attributable to pre-mature mortality due to stroke for those younger than 65 was calculated across their potential working life. These lost potential lifetime earnings, based on multiplication by mean earnings of UK workers in different age bands for 2004 [21], were discounted at 3.5% [22]. The rate of economic productivity, the current unemployment figures and the friction period were also factored in [23, 24]. Estimate on friction period was obtained from Koopmanschap et al. [25]. The income loss from stroke-related morbidity was conservatively estimated by multiplying the annual number of certified days off work from stroke with the mean daily earnings [26]. Direct income payments relating to stroke morbidity were based on data on the Payments for Disability Living Allowance, Attendance Allowance and Incapacity Benefit Payments made to sufferers of stroke as documented by the Department of Work and Pensions [27].

All unit costs reported were adjusted to 2005 prices [28] and are provided in Table 1.


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  		Table 1. Main unit cost and resource use items

 
Finally we carried out a deterministic sensitivity analysis to test the robustness of the model and to identify important areas of uncertainty around our assumptions. For that, we varied all the individual resource use volumes and unit costs volumes by 10 and 20%. Also we varied the incidence and prevalence rates used to calculate the acute and chronic phase treatment costs. For incidence rates we again used 10% and 20% higher and lower incidence rates than the SLSR rates. For prevalence rates we used the rates from two previously published studies [29, 30], which estimated higher and lower prevalence rates than our baseline prevalence estimate [9], to allow for the wide range of estimates gained from such studies.


   Results
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 Abstract
 Introduction
 Methods
 Results
Discussion
 Key points
 Funding
 Supplementary Data
 References
 
This study estimates the cost of stroke care to be around £9 billion a year (Table 2). Total annual direct care cost is estimated to be approximately 49% of this total; informal care around 27% and the indirect costs approximately 24%.


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  		Table 2. Total costs

 
It was estimated that a total of around 200,000 individuals were in need of some sort of assistance, either from professional carers or from family members, to carry out daily living activities. The estimated cost of informal care for these individuals was estimated to be £2.5 billion. Productivity losses due to death and disability were estimated to be approximately £1.5 billion.

Altering the incidence rates above and below the baseline rate did not have a significant impact on the total costs (Table 3). A one-way sensitivity analysis for each of the resource use and unit cost items was also undertaken. None of the individual items had significant impact on the overall costs. Multivariate sensitivity analysis on the group of unit cost variables and separately on the group of resource use variables was also undertaken. The impact of changing the unit cost variables by 20% had a bigger impact on the total costs than the impact of changing all resource use items by 20% (please see the table in Appendix 3, available on Age and Ageing online).


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  		Table 3. Sensitivity analysis table (1,000,000 £’s)

 
On the other hand, changing the prevalence estimates did have a significant impact on the costs estimates. This merely reflects the fact that stroke is a chronic disease. Varying the prevalence estimates gave rise to total annual direct care costs ranging from £3.6 billion to £4.8 billion and informal care costs ranging from £1.885 billion to £2.762 billion (Table 3).


   Discussion
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 Abstract
 Introduction
 Methods
 Results
 Discussion
Key points
 Funding
 Supplementary Data
 References
 
This study estimates the cost of stroke in the UK to be associated with the total annual direct cost of stroke at approximately £4 billion or approximately 5.5% of the total UK expenditure on health care. Within an international context, Evers et al. reported the percentage of health care expenditures arising from stroke in six developed countries to be 3% on average [31]. Previous estimates suggest that in the UK stroke consumes more than this average with total direct health care expenditure on stroke falling between 4 and 6% of National Health Service expenditure [32]. This study suggests that the true percentage of health care expenditure on stroke probably lies towards the upper end of estimates gained from these earlier UK studies. The most recent study, using a top-down approach to estimate the cost of cerebrovascular diseases in the UK reports estimates, which are in line with those reported here if benefit payments are accounted for [33].

If the costs of informal care and lost productivity due to stroke are included a total cost of £9 billion a year is incurred by the UK through stroke. The implication is that the chronic phase of this disease is the most costly and a better understanding of long-term care in terms of its effectiveness and cost-effectiveness is warranted.

In this study, we adopted a costing approach, which differentiated between the acute and chronic treatment phases. To do so, the method uses information on incident cases (as well as recurrent strokes) to estimate the costs attributable to the acute phase of management and uses prevalence data to estimate the costs attributable to the chronic phase of management. Surprisingly, perhaps the treatment cost estimates were not sensitive to variations in the incident rate. In order to test the sensitivity of the costing model to incidence rates, this was varied by 20% with little impact. While it is argued that this reflects the importance of the chronic nature of the disease, a fact borne out by the indirect costs being twice those of the direct costs, it should not imply that data relating to incidence should be disregarded. Other studies support this finding that informal care can make up a significant part in total costs of care [34, 35]. (Please see the text in Appendix 4, available on Age and Ageing online.) That said the chronic nature of stroke and the relative importance of the on-going cost of the disease implies that this chronic phase of the treatment episode is vitally important. Just as epidemiological data on incidence are varied, it is the case with the prevalence literature. Moreover, there is a dire lack of evidence on the effectiveness and cost-effectiveness of long-term and follow-up care in this area. Given the importance of the chronic care phase as highlighted by this and other studies [36], it would suggest that more attention be paid to these matters. Coupled with the recent National Audit Office's findings that the efficiency and effectiveness of stroke treatment varies considerably across the NHS [37], this high cost ought to prompt re-consideration of the management of stroke services within the NHS.

Patient-based registers such as the SLSR can be useful in providing basic, yet fundamental information required to document longer term treatment options and are important resources to health service planners. The SLSR is the only stroke patient population-based register in the UK, which has data on the resource use of stroke patients over 10 years of follow-up. Therefore, it is the most reliable source of information for making estimates on the use of health care by stroke patients. Whilst in the social sciences it is common for research bodies to now fund the collection of primary data on an on-going basis, this is, unfortunately, less prevalent within the health care sector.

This study has a number of limitations. For example, the baseline incidence figures and majority of resource use items are taken from the SLSR. Although SLSR collects data on patients from a specific geographic location of London with a specific multiethnic population, we have accounted for possible variations in our data by carrying out a sensitivity analysis on all the variables used, including the incidence rates. (Please see the text in Appendix 5, available on Age and Ageing online.)

What is clear is that the generally high-estimated cost of stroke in the industrial economies is a result of the high prevalence of the disease. Despite the relatively high mortality, the long-term needs of patients left disabled following stroke places an on-going commitment of resources on every health care system. Moreover, the prevalence and hence the burden of stroke is expected to grow in the future as a result of the increase in the proportion of older people in the society. Therefore, cost of illness studies have to be updated to understand the economics of the diseases and its changing cost structure. This will enable policy makers to have a better understanding of the factors, which have an impact on the expenditures of costly diseases such as stroke and also allow better-informed distribution of resources.


   Key points
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Key points
Funding
 Supplementary Data
 References
 

  • This paper presents the costs of stroke in the UK from a societal perspective. The total societal costs are £8.9 billion a year and represent 5% of NHS costs.
  • There is space for improving the provision of care, which in return will affect the overall cost profile.
  • There is a need for research exploring the economic impact of cost effective solutions on the economic burden of stroke in the future.


   Funding
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 Key points
 Funding
Supplementary Data
 References
 
The authors acknowledge financial support from the Department of Health via the NIHR comprehensive Biomedical Research Centre award at Guy's & St Thomas' NHS Foundation Trust in partnership with King's College London and King's College Hospital NHS Foundation Trust.


   Supplementary Data
Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
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 Funding
 Supplementary Data
References
 
Supplementary data are available at Age and Ageing online.


   Acknowledgements
 
The authors would like to thank Dr Anthony Rudd and Ms Cathy Coshall for the help they provided throughout the study.


   References
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 Abstract
 Introduction
 Methods
 Results
 Discussion
 Key points
 Funding
 Supplementary Data
 References
 

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Received 3 February 2008; accepted in revised form 26 August 2008.


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