It's more than 80 years since insulin was discovered. So why have doctors not made more progress in fighting diabetes? Jeremy Laurance reports

For most children, an ice cream is a simple treat. But for Nick Taylor, enjoying one involves a complex calculation of carbohydrate content, blood-sugar levels and insulin. Nick is diabetic, and, until a month ago, an ice cream came with a sting in the tale. If his mother Sally allowed it, she would have to watch him like a hawk in case his blood sugar rose too high, and he developed ketoacidosis and passed out.

For most children, an ice cream is a simple treat. But for Nick Taylor, enjoying one involves a complex calculation of carbohydrate content, blood-sugar levels and insulin. Nick is diabetic, and, until a month ago, an ice cream came with a sting in the tale. If his mother Sally allowed it, she would have to watch him like a hawk in case his blood sugar rose too high, and he developed ketoacidosis and passed out.

If she disallowed it, it would be a cruel reminder to an eight-year-old boy of the condition that shackles 20,000 children in the UK to a regime of injections and rigidly controlled diets.

That is the reality for most sufferers from diabetes. It is more than 80 years since the discovery of insulin, in 1922, yet we still cannot treat the condition properly, let alone cure it. Some of those who worked on insulin in the early years, such as Frederick Sanger, were awarded the Nobel prize. But we do not know how to deliver insulin in a way that leaves the body undamaged.

Last week, a report by Diabetes UK spelt out the huge human and financial cost of the condition that is predicted to affect three million people in the UK by 2010. Diabetics suffer complications from their treatment that make them prone to lose their sight and their legs - the result of circulation problems in the retina and the limbs. They are at higher risk of heart and kidney disease. And if they don't control their blood-sugar level, they may lose consciousness, lapse into a coma and die.

Sue Townsend, the creator of Adrian Mole, is almost blind and in a wheelchair because of diabetes. She describes how she has had "lots of surgery" to try to save her sight, and has developed Charcot's joint, a rare bone condition linked with diabetes. "I always knew diabetes might eventually cause sight problems... but I didn't expect to lose my sight quite so fast," she says.

Ms Townsend has Type II diabetes - the kind that develops in adulthood. In addition to the 237,000 affected by Type I "insulin dependent" diabetes, of whom 20,000 are children, there are a further one and a half million adults diagnosed with Type II - many of them also requiring insulin injections (a further one million are estimated to remain undiagnosed). Treatment for Type I alone costs an estimated £2.5bn a year - around £7,000 a patient - for a lousy result. Treatment for Type II costs billions more.

It is, in short, a story of medical failure. We are so accustomed to reading about miracle cures in medicine that this comes as a shock. Given that the cause of diabetes - a lack of insulin - was identified almost a century ago, why has there not been more progress in tackling one of the worst chronic diseases in the Western world?

There have been some developments. Nick Taylor has been eating ice creams all summer, thanks to an insulin pump fitted at the beginning of August. He has been diabetic since he was two, and in that time his mother Sally estimates that he has had between 7,000 and 9,000 blood tests. He also faced three to four injections a day - at every meal and before bed. "When he was three, I had to hold him down. It was horrific. When he went wobbly with low blood sugar, I had to cram Lucozade tablets into his mouth. As a young child, he didn't understand his symptoms," she says.

That task has been eased by the pump, strapped to Nick's waist, which can deliver a measured dose of insulin at the touch of a button. This can be adjusted to precisely cover the meal or snack being consumed, without the need for an extra injection. For a sugary treat, the pump is the only way to manage it. "You can't give an injection tiny enough for an ice cream. I would either have let his blood sugar rise or not allowed him to have it. This way, we can keep his blood sugar much more stable," says Sally. For Nick and his family, the pump represents a significant advance. But it's not much to show for 80 years of scientific research.

Nick has tried other innovations - there was a wristwatch-like monitor that was supposed to provide a blood-sugar reading updated every 20 minutes. "We found it took three hours to warm up, and every time you moved, it stopped working," says Sally.

As the burden of diabetes grows, the need for better care has become more urgent. The incidence of Type I diabetes doubled in children between 1985 and 1995, and Type II diabetes is also rising rapidly, driven by the growth in obesity. Treating diabetes is now one of the biggest challenges in medicine.

Last month, the National Institute of Clinical Excellence (Nice) published guidelines to improve care for children and adults with Type I diabetes in the UK. At the same time, a two-year programme in more than 100 GP practices, led by the National Primary Care Development Team, reported big improvements in blood-sugar, cholesterol and blood-pressure control among 24,000 diabetic patients after just 10 months. If extended nationwide, the scheme could save 11,000 lives over a decade, the organisers claim.

But these measures are aimed at controlling the symptoms, not tackling the cause of the disease. Stephen Greene, a consultant paediatrician at the University of Dundee and the chair of the group that drew up the Nice guidelines for children, says: "Although we have this so-called magical cure - insulin - it doesn't cure over a long period. It is given in the wrong place, at the wrong time and in the wrong dose. The aim is to maximise the effects of insulin therapy and minimise the damage."

In diabetes, the glucose in the blood that comes from the digestion of carbohydrates such as bread, potatoes, cereals and sweet foods rises too high, because the body cannot use it properly. A normal pancreas produces insulin, which is essential to help the glucose enter the cells. It does so in a continuous drip-drip process, which keeps the level of sugar in the blood under constant control. That is impossible to mimic with injections of insulin in substantial doses which, at best, cause the blood-sugar level to seesaw up and down.

Ever since insulin was discovered in the 1920s, companies have sought ways of making it longer-lasting, so that patients could manage on just one or two injections a day. But that would mean allowing blood sugar to rise to two or three times its normal level while awaiting the next dose of insulin. High blood-sugar levels over years do long-term damage to eyes, heart, kidneys and circulation. Since the synthesis of human insulin in the late 1970s, the strategy has changed. Now, the gold standard is intensive insulin therapy - four or five doses a day, either by injection or pump, combined with a long-acting insulin given in a single injection once every 24 hours.

Research is underway for more radical solutions, but, as Dr Greene says: "The glory goes to the people who make discoveries in medicine, but we are left trying to persuade teenagers to take their insulin day after day. We have to motivate people. That is the challenge."

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