MEDICAL MATTERS:A recent study from China poses a lot of interesting questions about diabetes, writes Tom O'Dowd
EVERYONE MUST now know someone with type 2 diabetes. In the body the beta cells in the pancreas gland secrete insulin which keeps the blood sugar at a healthy level. When the beta cells come under pressure from prolonged and excessive sugar intake they malfunction.
This causes the blood sugar to increase which in turn causes more beta cell malfunction. Well, that is the theory anyway.
We know that poor sugar control causes type 2 diabetes to get worse over time. Indeed, a famous study on diabetes in the UK noted that 30 per cent of people with type 2 diabetes ended up on insulin.
Specialists have been transferring diabetes patients from tablet hypoglycaemics to insulin injections at an earlier stage of the disease. What about starting patients on insulin as soon as they develop diabetes?
A recent study from Gaungzhou in China has thrown up a lot of interesting questions. They entered 382 newly diagnosed patients with diabetes into a trial of insulin or metformin, a commonly prescribed oral hypoglycaemic.
After eight days everyone had reached normal blood sugar levels as expected. They continued treatment for another two weeks and then stopped both insulin and tablets. Patients were kept on diet and exercise regimes while off the treatment.
They followed the patients carefully for a year and the findings were astonishing. Fifty per cent of those who were in the insulin arm of the study had normal blood sugars a year later.
The 27 per cent of those on tablets (metformin) had normal blood sugars a year later. The authors use the term "remission" borrowed from cancer treatment. What is more, insulin secretion returned to normal in the remission groups indicating that the beta cells had returned to normal.
The findings are of course encouraging for people with newly diagnosed diabetes. The authors' explanation for their findings are, if anything, even more interesting.
Generations of doctors have been taught that glucose is toxic to the beta cells in the pancreas and that reduced sugar intake is the only answer. The Chinese authors offered a radical interpretation of their success.
They said they were replacing insulin and that it provided "a type of beta cell rest". The rest allowed the beta cells to recover their ability to produce insulin and restore all kinds of physiological activities in the body.
It was a very well conducted study and was accompanied by a commentary from Canadian colleagues who seem to be taken as much by the idea of resting the pancreas as they do by the success of insulin in particular.
I have been watching the letters to the editor to see if colleagues have spotted flaws in their research design. In medical research there seems to be a tradition of colleagues writing nice personal letters to authors when they agree with the findings. Those disagreeing write robust detailed letters to the editor which are published with some relish, or so it seems. The letters have been respectful and note areas that need clarification.
There are big implications for the way we manage newly diagnosed patients with diabetes. Instead of keeping insulin as a last resort it now seems it has a role early on in the disease.
A number of questions arise that will need much more research. For example, how long will the remission last?
It is notable that most of the patients in the study would be considered of normal body mass index in Ireland but our BMI scales are not applicable to those of Chinese origin.
It is also of interest that they kept patients on exercise and diet regimes. What happens if patients discontinue diet and exercise - as often happens?
If patients relapse what should happen? Should they be given another "short, sharp shock" of insulin. This study will set a lot more research questions running for the benefit of patients. Patients with diabetes and their families will be beneficiaries of the good research that is going on in Ireland and internationally.
One of the many good things that has come out of a thriving Chinese economy is increased medical research activity and this study is an example. The authors' interpretation of their success as resting the beta cells of the pancreas is novel and perhaps related to the long tradition of Chinese medicine which is poorly understood in Western cultures.
This research is based on newly diagnosed patients and casts no new light on patients with longstanding diabetes. Research has, however, a habit of taking us into new places and offering us new insights that are sometimes transferrable to other diseases. Who knows what it may offer those patients with established diabetes.
For those who want to read further it is published in The Lancet on May 24th 2008
Tom O'Dowd is professor of general practice in Trinity College Dublin and a practising GP