APPENDIX 6
Memorandum by Mr Alexander Cohen (VT9)
INTRODUCTION
Venous thromboembolism (VTE) consists of two
related conditions: deep vein thrombosis (DVT) and pulmonary embolism
(PE). In general, venous thrombosis is defined as a pathologic
event in which a blood clot partially or totally occludes a vein.
DVT usually occurs in the deep veins of the calf muscles and,
less commonly, in the proximal (more central) deep veins of the
leg and upper extremities.
VTE is a potentially lethal disease with death
most often occurring as a result of PE. Death can occur when the
venous thrombi break off and form emboli, which pass to and obstruct
the arteries of the lungs. Diagnosis of PE often occurs too late
in the disease course to provide effective treatment. Most clinical
studies report the incidence of DVT to be approximately twice
that of PE1. VTE is a major public health problem and is both
prevalent and costly2. Over half of all VTE is associated with
recent hospitalisation with medical and surgical conditions having
similar attributable risk (about one quarter each)2.
Management of VTE comprises both prophylaxis
and treatment of DVT and PE, plus management of the long-term
sequelae of VTE, including post-thrombotic syndrome (PTS). Until
recently, the majority of care was given in a secondary (hospital)
setting, but long term secondary prevention is also managed by
primary care physicians.
ESTIMATING THE
BURDEN AND
COSTS
Two approaches can be taken and these are described
below.
The available data from population based epidemiology
studies can be used to calculate the burden and costing this problem.
However, this incidence-based approach may not assess much of
the burden from hospital costs in high risk groups who require
preventive therapy, as it is based on reported events. VTE is
notoriously inaccurately reported with rates as low as 30% being
found in many studies. It also does not assess asymptomatic events
which can have both short term and long term sequelae and costs
It is also possible to do similar calculations
using a "bottom up" approach. The "bottom up"
approach examines hospital and community data, as well as assessing
at risk populations and then annualises the current and future
resource use for estimating the burden and cost. However the "bottom
up" approach cannot estimate the burden of sudden death or
undiagnosed mortality from this condition (in the absence of data
from prospective cohorts or country specific autopsy data).
We have recently undertaken a review of the
burden and cost of venous thromboembolism using these two approaches
to check the validity of each other, with the known limitation
that they will measure different things. The results are presented
below.
INCIDENCE-BASED
APPROACH
The most robust European data come from the
only two population based epidemiology studies from Nordstrom3
and Oger4 which have shown new (incident) DVT rates as 117 per
100,000 and 87 per 100,000 respectively (pooled estimate is 99
per 100,000 population). New (incident) PE rate was only reported
in Oger4 and was 46 per 100,000. Lindblad and coworkers have shown
in a population based autopsy study that autopsy diagnosed fatal
PE occurs in around 40 per 100,000 population5. The original estimate
of 40 fatal PEs per 100,000 (93 in 230,838 population) in the
Linblad paper was based on an autopsy rate of 76.9%. Assuming
100% autopsy rate, fatal PEs rate was re-calculated as 52 per
100,000 population. Heit et al6)reported that 10.7% of the new
PE cases would die within 14 days of hospitalisation, therefore
these patients would already be counted as new non-fatal PEs.
In order to avoid double counting, 10.7% of 52 per 100,000 were
excluded, which gave the final estimate of sudden fatal PEs as
47 per 100,000 population.
Therefore new cases of VTE has an estimated
incidence of 145 per 100,000 diagnosed premortem and 47 per 100,000
diagnosed at post mortem in the developed world and hence is an
important cause of morbidity and mortality3, 4, 5. One study reports
that 11% of patients do not survive to one hour post PE event7.
Initial treatment of DVT and PE is costly and patients who have
DVT often develop serious long-term complications,8 which inevitably
add to the cost burden on the Health Services9, 10.
"BOTTOM UP
" APPROACH:
The hospital data model estimates approximately
49,000 expected annual cases of hospital acquired DVT and over
11,000 cases of Pulmonary Embolism. The community model estimates
over 55,000 expected annual cases of community acquired DVT and
over 20,000 cases of Pulmonary Embolism.
The cost of illness (COI) model comprises two
components, a community VTE algorithm and a hospital induced VTE
algorithm. The hospital models annual costs for VTE management
in the UK are estimated to be around £280 million. The community
model costs are estimated at £360 million.
The total cost burden (direct and indirect costs)
to the UK of management of VTE is estimated at approximately £640
million. Approximately 60% of this total is attributable to community
rather than hospital based incidence. Inpatient treatment costs
account for almost 50% of the total cost burden and approximately
20% of costs are attributable to the chronic care costs of PTS.
SUMMARY OF
THE RESULTS
INCIDENCE-BASED APPROACH
| DVT | PE
| Total VTE | Cost (£million)
|
| UK Population | 59,000 |
27,000 diagnosed | 114,000 |
340 |
| | 28,000 sudden death
| | |
| | |
| |
BOTTOM UP APPROACH
| DVT | PE
| Total VTE | Cost (£million)
|
| Community | 55,000 | 20,000
| 75,000 | 360 |
| Hospital | 49,000 | 11,000
| 60,000 | 280 |
| Total UK Population | 104,000
| 31,000 | 135,000 | 640
|
| | |
| |
SUMMARY
Whichever approach is taken it is clear that VTE is a major
burden and cost to the UK and the NHS. The variation in figures
reflects that the different approaches measure different things.
VTE is a condition that is associated with medical and surgical
settings and occurs in the community and hospitals. Most people
are aware of travel related VTE, but the other associations, in
particular hospitalisation are more common and require attention.
The utilisation of appropriate and effective prevention (thromboprophylaxis)
results in a reduction in the burden of 60-80% that would lead
to major cost savings and, more importantly, a reduction in morbidity
and mortality11-14.
November 2004
REFERENCES 1 White RH.
The epidemiology of venous thromboembolism. Circulation 2003;
107(23 Suppl 1):I4-I8.
2 Heit JA. Venous thromboembolism epidemiology: implications
for prevention and management. Semin Thromb Hemost 2002; 28 Suppl
2:3-13.
3 Nordstrom M, Lindblad B, Bergqvist D, Kjellstrom T.
A prospective study of the incidence of deep-vein thrombosis within
a defined urban population. J Intern Med 1992; 232(2):155-160.
4 Oger E. Incidence of venous thromboembolism: a community-based
study in Western France. EPI-GETBP Study Group. Groupe d'Etude
de la Thrombose de Bretagne Occidentale. Thromb Haemost 2000;
83(5):657-660.
5 Lindblad B, Sternby NH and Bergqvist D: Incidence of
venous thromboembolism verified by necropsy over 30 years. BMJ,
1991; 302: 709-711.
6 Heit JA, Silverstein MD, Mohr DN, Petterson TM, Lohse
CM, O'Fallon WM et al. The epidemiology of venous thromboembolism
in the community. Thromb Haemost 2001; 86(1):452-463.
7 Kearon C. Natural history of venous thromboembolism.
Circulation 2003; 107(23 Suppl 1):I22-I30.
8 Heit JA. Risk factors for venous thromboembolism. Clin
Chest Med 2003; 24(1):1-12.
9 Bergqvist D, Jendteg S, Johansen L, Persson U, Odegaard
K. Cost of Long-Term Complications of Deep Venous Thrombosis of
the Lower Extremities: An Analysis of a Defined Patient Population
in Sweden. Annals of Internal Medicine 1997; 126(6):454-457.
10 Cohen A, Botteman M, Stephens J, Ewing M, Collier P, Pashos
C et al. Cost effectiveness of two anticoagulants for the prophylaxis
of DVT and subsequent long-term complications (PTS and recurrent
VTE) in total hip replacement surgery in the United Kingdom. Poster
Presentation. XVIIIth Congress of the International Society on
Thrombosis and Haemostasis, Paris, France. Thromb Haemost 2001;
suppl—CD-ROM.
11 Geerts W et al Prevention of venous thromboembolism. Seventh
ACCP Recommendations. Chest 2004; 126:338S-400S
12 Samama MM, Cohen AT, Darmon J-Y, et al. A comparison of
enoxaparin with placebo for the prevention of venous thromboembolism
in acutely ill medical patients. N Engl J Med 1999; 341: 793-800.
13 Cohen, AT, Davidson BL, Gallus AS, Lassen MR, Tomkowski
W, Turpie AGG, Cariou, Egberts JFM, Lensing AWA. Fondaparinux
for the Prevention of VTE in Acutely Ill Medical Patients. Blood
2003;102: Abstract number 42.
14 Cohen AT, Edmondson RA, Phillips MJ, Ward VP, Kakkar VV.
The changing pattern of venous thromboembolic disease. Haemostasis
1996; 26: 65-71
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