A landmark study shows that the life-threatening complications of the most common form of diabetes can be substantially reduced by more intensive management of existing treatments. But what are the cost and service implications for the NHS? Rhonda Siddall

Earlier this year health secretary Frank Dobson announced that the national service framework initiative, which aims to set national standards for treatment of diseases and conditions, would focus next on diabetes. Full details have yet to be announced, but the government has promised that a set of national diabetes standards will be published in 2001. They could not come at a better time.

Diabetes affects some 1.4 million people in the UK. But cases are set to increase by more than 1.5 million over the next decade, reflecting a global trend that will see the illness nearly double by the year 2010.

Cases of type-1 diabetes - which has a sudden onset, usually before the age of 40, and means that insulin will always have to be taken if the patient is not to lapse into a diabetic coma - are predicted to fall. But cases of type2 diabetes - the most common form affecting about 90 per cent of people with diabetes - are predicted to explode.

About 2 per cent of the population and 8 per cent of people in their sixties have type-2 diabetes, which affects people mostly over the age of 40 and has a slow onset that may go undiagnosed. People with type-2 diabetes still secrete insulin but, for a variety of reasons, not enough is available for the body's needs.

The rising elderly population, Western-style diets and the increasing tendency to take less physical exercise are all thought to be factors explaining the massive and growing type-2 diabetes problem.

It is estimated that diabetes costs the NHS well over£2bn a year, consuming between 5.5 per cent and 9.4 per cent of NHS resources. The£123m spent on anti-diabetic medication is only a fraction of the overall cost of care.

The consequences for the NHS of the rise in type-2 diabetes are enormous.

Professor Stewart Cameron, emeritus professor of renal medicine at Guy's, St Thomas' and King's College Hospital renal unit in London, says:

'People with type-2 diabetes are expensive patients to treat, wherever and however they are treated. These patients used to die from the complications they are prone to. But now they are surviving longer, they die slowly and expensively and present a major burden to the NHS.'

People with type-2 diabetes can be treated with a range of medicines and may or may not require insulin.

Patients usually present with thirst, weight-loss and tiredness.

Type-2 is often mistakenly referred to as the 'mild' form of diabetes because it can be initially treated with drugs and diet. But it is a progressive condition that can lead to a variety of serious complications, which arise through damage to the blood vessels.

If the damaged blood vessels are small, then blood supply to the eyes, kidneys and various nerves may become restricted. Over time, this can lead to damage to the retina in the eye and to impaired sight (retinopathy), to kidney disease and to pain and loss of sensation in the legs and feet. If large blood vessels are damaged, there is an increased risk of hypertension and heart disease.

Coronary heart disease accounts for more than 55 per cent of deaths from diabetes, people with type-2 diabetes are two to three times more likely to suffer strokes than the general population, and diabetes is the leading cause of blindness in the UK.

But there is good news for patients.

Last year, the results of the largest clinical trial of diabetes ever attempted - the 20-year,£22m UK prospective diabetes study - showed for the first time that the life-threatening complications of type-2 diabetes can be substantially reduced by more intensive management using existing treatments.

It was a landmark piece of research, as Dr Peter Watkins, consultant physician at King's College Hospital and member of the study's ethics and data monitoring committee, explains.

He says: 'This was a fantastic study, a great achievement for British clinical medicine. Until this study, there was very little data on reducing diabetic complications in type-2 diabetes.'

Led by researchers at Oxford University, the study revealed that better blood glucose control reduces the risk of eye disease by a quarter and of early kidney damage by a third.

It also revealed that better blood pressure control reduced both the risk of strokes and of death from longterm complications of diabetes by a third.

Study leader Professor Robert Turner, professor of medicine at Oxford University, says: 'Diabetic complications are often regarded as being a natural outcome of this chronic disease. But the study showed definitively that good management helps to prevent complications.'

In the study, blood glucose and blood pressure levels were measured every three months rather than annually, as is current practice. If either blood glucose or blood pressure were above an agreed target, the treatment dose was increased or other treatments were added.

But while these findings may be good news for patients, what of the cost and service implications for the NHS?

Dr Watkins says: 'The UKPDS findings have considerable resource implications. The demands made by the UKPDS for higher standards require greater input into education, training and monitoring of patients.

It's a tough job for health authorities.'

A health economic analysis of the study showed that improved blood pressure control in people with diabetes was cost-effective - the effect would be to save the NHS between£260 and£720 for every year of a patient's life without symptoms.

5The analysis found that the increased cost of medication for improving blood pressure control was directly recouped by the lower costs from fewer clinical complications.

However, the nursing and physician costs related to more intensive management were not.

Director of Oxford University's health economics research centre, Dr Alastair Gray, who conducted the analysis, says: 'In comparison with other preventive strategies currently in place, such as cholesterol lowering for reducing cardiovascular risk, intensive management of diabetes is cost-effective.'

The British Diabetic Association has called for the UKPDS recommendations to be fully incorporated into clinical practice.

One of the most striking features of the study was the progressive nature of type-2 diabetes. The study revealed that up to 50 per cent of people with newly diagnosed type-2 diabetes already showed early signs of complications.

In a statement released earlier this year, the BDA said: 'This emphasises the need for early detection of diabetes and screening for diabetes of those in high-risk groups, such as those who are over 40, those who are overweight, those of Asian or African Caribbean origin, those with a family history or those with a prior history of gestational diabetes.'

The BDA is currently in discussions with the National Screening Committee, which is assessing the implications of opportunistic screening of people at high risk of type-2 diabetes.

But best clinical practice, as outlined in the UKPDS study, is a long way from what is happening on the ground in some HAs. Screening for microalbuminuria in urine - a simple, cheap test that is an important predictor of renal disease - is frequently not performed. 'This test can be done by any GP or general physician but many diabetics roll up in renal units never having been tested, ' says Professor Cameron, who adds that best clinical practice as outlined by guidelines tends to be implemented when purchasers pay attention to recommendations.

'Clinicians are given money if an HA decides something is a sufficient health priority and it is cheaper in the longer term to do so, ' he says.

Bridget Turner, the BDA's healthcare delivery officer, says that standards of care for type-2 diabetes vary enormously between HAs.

'Much of what we know about standards is based on anecdotal evidence because there is little documented comparative evidence.

But from the calls we receive it seems that what's available depends on where you live. Some areas have policies for retinal screening that cover the whole district. But others don't.

'Access to chiropody is another issue. It is becoming increasingly difficult in some areas to find a state registered chiropodist, ' adds Turner.

The BDA set up the UK Diabs (diabetes, information, audit and benchmarking system) Project two years ago to try to get a handle on what was provided where, and how diabetics fared according to various outcome measures relative to where they lived. Forty HAs have provided data for the comparative audit, which has yet to publish its results. Project manager Malcolm Roxburgh says the data will be used by the BDA to campaign for improved services.

Mr Roxburgh says: 'All districts measure the majority of things recommended in diabetic protocols.

But some districts are not as good as others at doing some things such as measuring visual acuity. In some districts, up to 98 per cent of patients are being measured. In others, only 20-30 per cent are being measured.

There is wide variation in the delivery of services.'

More worryingly, the preliminary findings of the project indicate large variations between districts in the rates of myocardial infarction and blindness. But Mr Roxburgh says this finding should be treated with caution because work remains to be done on assessing whether such variation is connected with population characteristics such as social deprivation.

Bradford HA, which serves the communities of Shipley, Bingley, Keighley, Ilkley and Bradford, ranks as the eighth most deprived HA area in the country. Poor health is reflected by high rates of diabetes, coronary heart disease, mental illness and accidents. Diabetes is more than four times the national average and deaths from coronary heart disease are more than double the national average.

The HA has 12,000 diagnosed diabetics on its register, but reckons that some 4,000 people who have diabetes are not accessing services.

Health services in the district are provided by four primary care groups, Airedale trust, Bradford Community Health trust, Bradford Hospitals trust and the West Yorkshire Metropolitan Ambulance Services trust.

The district, which is a health action zone, is set to receive£10m from central government over the next three years. Diabetes is one of its key priorities.

Andrew Kenworthy, assistant director of planning and HAZ coordinator, says: 'We have agreed a three-stage approach to tackle inequalities. We want to establish an equitable and sustainable service across the district, identify undiagnosed diabetics and ensure that mainstream health and social services are strengthened to cope with subsequent demands for service.'

The HA has a population of 486,000, but this is forecast to rise to 511,000 by 2001 with the largest change predicted in the ethnic minority population, which has a higher incidence of diabetes.

Last October, the HA held a conference - 'Diabetes, shaping the future' - at which almost 300 people with first-hand knowledge of diabetes shared their experiences with professionals and managers responsible for service delivery.

One of the key themes to emerge was that many solutions to better services could be found not by more money, but by more effective working, through better co-ordination and communication between authorities and communities (see box, above left).

Mr Kenworthy says: 'We are aiming to move away from a traditional approach to diabetes planning to a more holistic model that reflects the wider needs of diabetic patients in the community. We are shifting the emphasis . We need to understand our communities and reflect that in the planning of services, rather than planning a standardised service for the population.'

Key to this plan will be the appointment of a link person to work with the South Asian community in Bradford to raise awareness about diabetes and to improve access to services.

Improving access to services for people with type-2 diabetes, and raising standards across districts, will help to relieve the burden on the NHS of the complications of the disease through earlier detection, more intensive management and screening.

But research on new approaches to drug treatment for diabetic complications may also offer hope. A new centre, the Oxford Centre for Diabetes, Endocrinology and Metabolism, due to open in 2001 at the Churchill Hospital, plans to evaluate new therapies and ways to administer insulin, and drugs that increase insulin output from the pancreas. It is being funded by£4.2m from the NHS capital programme and£4m from pharmaceutical company Novo Nordisk.

The pharmaceutical industry is also focusing on new areas for potential drug development for diabetic complications (see box, below). But it will be a number of years before such new treatments are available to doctors.

Meanwhile, as Professor Cameron says: 'There is light at the end of the tunnel. But diabetes is a major, growing problem. We are looking at the disease having a larger and larger impact on the health service.'

Type-2 diabetes: the facts

What is it?

Diabetes mellitus is a common endocrine disorder in which the amount of glucose in the blood is abnormally high because the body is no longer able to use it adequately as a source of energy.

Causes

These are unclear, but there is believed to be a genetic influence involving several genes.

Symptoms

The main symptoms of untreated diabetes are increased urination, increased thirst, itching of the genitals, weight-loss, extreme tiredness and blurred vision. Onset of these symptoms is usually gradual.

Complications Diabetes is the single biggest cause of blindness among adults of working age in the UK. People with diabetes account for more than 16 per cent of coronary heart disease-related hospital admissions. Half of all lower limb amputations, other than those following trauma, are a consequence of diabetes. Diabetes is one of the most common causes of kidney failure.

Costs It is estimated that the combined cost of treatment for type-1 and 2 diabetes is at least£2.2bn, or 5 per cent of NHS costs.

The Bradford model Current staffing levels for diabetic specialist nurses result in children often having long waits in clinics, causing them to miss school time. Bradford health authority is to appoint two additional paediatric diabet ic specialist nurses - one at Airedale trust and one at Bradford Hospitals trust. Money will also be given to paediatric specialist nurses to extend education about of diabetes in the wider community.

The HA aims to integrate information about diabetes into the mainstream school curriculum via a CD Rom - particularly targeted at schools with a high ethnic minority population - to increase understanding among teachers about diabetes.

A lack of understanding of the disease has been identified as leading to unnecessary and inappropriate ambulance journeys to hospital.

The HA is working with the Benefits Agency to set up workshops to serve as an information point for diabetics about benefits entitlement. These will reduce pressure on mainstream health services.

Seventeen satellite diabetic clinics have been set up in Bradford. In these clinics, 90 per cent of maintenance diabetic care is provided, supported by GPs accredited in secondary care of diabetes and specialist diabetic nurses. Only patients with acute needs are referred to hospital.

The HA aims to instigate a quality audit to ensure that satellite clinics are providing a high standard of care. A consultant provides community-based support.

A diabetes co-ordinator has been appointed to take forward the HA's diabetes agenda. This person will work with all the organisations that have an impact on the lives of people with diabetes. A campaign of early detection through primary care is going to be launched.

The HA is also aiming to appoint a link person to improve access to services and to promote health among people from communities of South Asian origin.

The HA will measure its success by detection of missing people with diabetes, prevention of complications of diabetes, 100 per cent coverage of targeted schools, 80 per cent of diabetes care delivered through primary and intermediate care, 100 per cent registration of people with diabetes on district register and evaluation of improvements including maintenance of employment for them.

The road ahead: reducing diabetic complications

The pharmaceutical industry is focusing on two areas for potential drug development for diabetic complications: aldose reductase inhibitors and advanced glycation end-product inhibitors.

ARIs inhibit the enzyme aldose reductase, which is found in many tissues, including the organs most susceptible to diabetic complications. It converts sugar into related molecules called sugar alcohols such as sorbitol, which can cause structural changes in nerves, for example, when produced in higher amounts, as in hyperglycaemia.

Advanced glycation end-products form in excess glucose conditions. They are modified proteins that, in simple terms, cannot function properly and as they accumulate cause damage to cells, tissues and blood vessels. Drugs that reduce accumulation of these proteins may show benefits against diabetic complications.

REFERENCES

1 A Amos, D McCarty, P Zimmit. The rising global burden of diabetes and its complications, estimates and projections to 2010. Diabetic Medicine 1997; 14 (supplement 5): 51-85.

2 Key Features of A Good Diabetic Service. NHS Executive, October 1997.

3 UK Prospective Diabetes Study Group.Tight blood pressure control and risk of macrovascular and microvascular complications in type-2 diabetes. Br Med J, 1998; 317 (7160): 703-13.

4 UKPDSG. Efficacy of atenolol and captopril in reducing risk of macrovascular and microvascular complications in type-2 diabetes. Br Med J 1998; 317 (7160): 713-19.

5 UKPDSG. Cost-effective analysis of improved blood pressure control in hypertensive patients with type-2 diabetes. Br Med J, 1998; 317 (7160): 7206.