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Consensus Conference on
Lipid Lowering to Prevent Vascular Events 17 & 18 March 1999
Consensus Statement
Coronary heart disease (CHD) is the most common cause of death in both
men and women in the UK and the prevalence of CHD is amongst the highest
in the world. It is a chronic progressive condition with its inception
in childhood.
An effective strategy for combating CHD needs action both at a population
level and directed at high risk individuals.
POPULATION STRATEGY
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An effective population based strategy must involve collaboration
between national and local government, health and education authorities
and other bodies to reduce the burden of risk in the population
and decrease the future need for treatment.
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Government policies should enable healthy choices. They need to
address the wider determinants of health such as social inclusion,
reduction in inequalities and unemployment. Consideration should
also be given to the policies concerning agriculture, food manufacture,
marketing and distribution, tobacco legislation, transport policy
and education.
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Health care professionals, through Royal Colleges and other professional
groups, should help inform such policy and ensure that health is
considered in all relevant policy contexts.
INDIVIDUAL STRATEGY
Large scale individual-based screening and intervention is not cost-effective.
However a strategy to enable behavioural change and reduce risk in high
risk groups is worthwhile. Interventions should be individually tailored
recognising culture, gender and affordability and willingness to change.
This may best be achieved by agreeing realistic targets.
Diet and lifestyle
The public requires consistent messages.
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Smoking cessation and reductions in excess alcohol, physical inactivity
and obesity are all important. Refer to existing guidelines (see
conference background papers).
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The key points in dietary management are increasing daily fruit
and vegetable consumption (aim for 5 portions a day); increase oil
rich fish (aim for 2 portions per week) and the proportion of unsaturated
fat; reduce saturated fat and salt intake. Although dietary change
has a modest effect on cholesterol level in individuals it has beneficial
effects on risk of CHD and other diseases. Dietary advice should
address weight management.
Lipid lowering drugs
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There is strong evidence to support the use of statins in those
at high absolute risk of CHD. These drugs are particularly effective
in reducing total cholesterol and LDL cholesterol. They have a smaller
effect on raising HDL and lowering triglycerides.
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The aim of statin treatment in both primary and secondary prevention
should be cholesterol <5mmol/l or a 25% decrease in serum cholesterol,
whichever is lower.
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Statins exhibit marked and consistent effects on lipid lowering.
The mortality evidence is currently restricted to simvastatin and
pravastatin. However, this evidence may need to be balanced against
the opportunity to treat more patients for a similar expenditure
with less rigorously tested statins and regimens.
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Fibrates may be used in patients with elevated triglycerides particularly
when associated with a low HDL. They may be more effective than
statins in decreasing triglycerides and raising HDL. Studies are
in progress looking at the effect of fibrates on CHD events, but
as yet mortality data are limited.
Hormone Replacement Therapy (HRT)
HRT has several effects which could lower CHD risk (including lipid
reduction) and observational studies suggest that it may be associated
with lower CHD mortality. The only randomised trial data, of HRT in
older women with CHD, has not shown overall benefit. HRT should not
however be withheld in women with menopausal symptoms and co-existing
CHD.
Aspirin
Aspirin treatment (75-300mg) is indicated for secondary prevention
in those without contraindications.
WHOM TO TREAT: SECONDARY AND PRIMARY PREVENTION
There is a continuum of risk for patients from those with the very
lowest risk to high risk patients with overt CHD. There is an overlap
in risk between patients with clinical disease, and those at highest
risk but without overt CHD. Risk relates to factors including age, gender,
smoking, lipid profile, blood pressure, ethnicity, inheritance and prior
disease.
DISTRIBUTION OF THE POPULATION VERSUS CHD RISK
The 30% ten year risk includes most patients with overt cardiovascular
disease (CHD) and the highest risk patients with no overt disease. Those
with the highest risk have the greatest potential to gain from treatment.
These are:
Patients with overt coronary heart disease (Secondary Prevention)
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Patients with CHD and total cholesterol of >5mmol/l or LDL >3
mmol/l should be offered treatment with a statin. Doubt still exists
about added benefit below this level.
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The relative reduction in CHD event rate by lipid lowering in clinical
trials is uninfluenced by age up to 75. Absolute risk increases
with age. Therefore, the number of older patients who need to be
treated to prevent one event is less than that of younger patients.
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Evidence for survival benefit from lipid lowering among those 70-75
years of age is weak (trials still underway) and the evidence is
absent for those over 75. Lipid lowering may be appropriate in those
over 70 years in the absence of serious comorbidity.
Patients with other major atherosclerotic disease (without
overt coronary disease) (Secondary Prevention)
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Patients with peripheral vascular disease or stroke have a high
incidence of CHD (diagnosed or undiagnosed). Although there is no
direct evidence, it is likely that such patients would benefit from
lipid lowering and it is therefore recommended that they are managed
as for those with overt CHD (i.e. secondary prevention).
Those whose absolute CHD risk exceeds 30% over ten years
based on multiple risk factor assessment (Primary Prevention)
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There is good evidence that statins are effective in primary prevention
for individuals at risk of CHD.
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Absolute CHD risk should be assessed from multiple risk factors
using charts or computer programmes based on the Framingham risk
equation (eg Joint British guidelines). Additional factors such
as family history, genetic hyperlipidaemia, renal disease, ethnicity,
socio-economic deprivation, serious co-morbidity and patient views
should also be considered in determining whom to treat.
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Individuals whose serum cholesterol is ³ 5 mmol/l and whose
CHD risk exceeds 30% over 10 years should be targeted first; but
there is compelling evidence to extend lipid lowering treatment
progressively to those at levels of risk as low as 15% over 10 years,
as resources and costs permit.
Diabetes
Familial hypercholesterolaemia (FH)
FH affects 1 in 500 of the population and is associated with a high
incidence of symptomatic CHD. For identification and management refer
to SIGN guidelines (in press) on Lipids and Primary Prevention of Coronary
Disease.
COST AND BENEFITS
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The financial costs involved in treating all groups who could potentially
benefit from lipid lowering are huge. NHS resources are finite and
therefore prioritisation is necessary. This should be based on evidence
based estimation of capacity to benefit.
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We recognise additional psychological and social costs of interventions
to prevent coronary disease.
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The cost effectiveness of lipid lowering interventions rises as
the absolute cardiovascular risk increases. The risk level at which
treatment is given needs to be influenced by both cost effectiveness
and overall cost but these are determined by the price of statins.
If prices were lower more people who would benefit could be treated
for the same resources.
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There are interventions in the prevention of CHD (e.g. lifestyle
changes) which are considerably more cost effective than statins
and these should already be in place when lipid lowering is initiated.
However, for the higher risk groups, cost effectiveness of statins
(at under £10,000 per life year gained) is on par with many
other interventions of proven effectiveness in other disease areas
provided by the NHS.
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Treating lower risk patients, even down to levels of absolute risk
of 15% over 10 years, would be more cost effective than some other
NHS interventions currently provided. However, both because of the
very large total expenditure that this would incur, and the problems
associated with withdrawing existing effective services elsewhere
we do not recommend that those at lower risk should be a priority
for treatment.
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In a typical Scottish practice of 10,000 patients it is estimated
that there will be 353 candidates aged 35 to 69 for secondary prevention
and 121 for primary prevention who have a level of risk of 30% over
ten years (see background papers). In areas of socio economic
deprivation the prevalence of CHD is higher and the need for lipid
lowering is greater. To avoid the substantial risk of the further
widening of health inequalities, general practices in areas of deprivation
will need extra resources to be able to respond to identified needs.
IMPLEMENTATION
CHD is a chronic progressive condition, mainly managed in Primary Care,
which requires ongoing long term resource investment. Practices should
develop a system of management for these patients including the use
of nurse led clinics. A stepwise and systematic approach is required.
Implementation strategy should be evidence based recognising the role
of the multidisciplinary team. To make this feasible it is necessary
to make available (through the Health Improvement Plan) all additional
resource requirements including training, monitoring, audit and additional
drug costs.
Most CHD patients will have contact with the Primary Care team within
a year. That opportunity should be used to recruit the patient into
secondary prevention. Many of those with non overt CHD will already
have risk factors being managed by the Primary Care team. They should
be the initial targets for primary prevention.
CONCLUDING STATEMENT
Health targets set by the government over the past decade have challenged
the NHS to reduce the burden of CHD in the UK. We now have the knowledge
about the dietary, lifestyle and pharmacological interventions to reduce
CHD morbidity and mortality. Effective and properly resourced lipid
lowering will improve the outcome in patients who can be identified
as being at high risk of CHD. However many individuals who will develop
CHD cannot yet be specifically identified by health professionals. Therefore
to reduce risk in the general population a clear commitment is required
of government to implement policies to empower people to minimise their
individual risk.
Lipid lowering should be available to the groups identified in this
document. Current resources substantially limit the implementation of
lipid lowering therapy.
BACKGROUND PAPERS
These will be published in Proceedings of Royal College of Physicians
of Edinburgh, Volume 29, April 1999 as a supplement.
Copies available from the Publications
Department at a cost of £5.00 each.
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