Most people who know about diabetes think there are two kinds: type 1, which you are born with, and type 2, which you get later in life from eating too much. This isn’t quite right, since the two types can occur at different life stages and for a number of reasons, but the broad distinction is well established in the public’s mind.
Now some doctors want to change all that and break the disease down into five subtypes, each with its own set of risk factors, outcomes and treatments.
This could be great news for people with diabetes, leading to more-tailored care. But the story is far from straightforward and it could be decades before we all start reaping the benefits of improved diagnosis.
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The new claim was made by researchers based in Sweden and Finland, who assessed almost 15,000 people with diabetes in those countries. They found that these people fell into one of five categories based on their blood sugar, their insulin production and sensitivity, and their body mass index and age. The subgroups also vary genetically.
The researchers say that two of the subtypes are mild, and can be largely treated with lifestyle changes and low doses of a drug called metformin. People with the three more severe forms are more likely to develop eye and kidney disease – and it is these individuals that doctors should prioritise.
Breaking down disease
So far, so good. After all, this is the way medicine is heading. The more we learn about common diseases, the more we realise there is huge variation in the way they present themselves. For example, research into the genetics of several cancers has helped identify which treatments might work best for individual people. And there is change under way in mental health, too, as new subcategories are beginning to be recommended for Ěý˛ą˛Ô»ĺ disease, among others.
So the idea that a cheap and fairly straightforward blood test, along with a note of a person’s age, height and weight, could help doctors predict the cause and prognosis of that individual’s diabetes – as well as the best treatment to use – is appealing. Especially considering that an are affected by the disorder and many aren’t getting the right treatment.
But the five subgroups aren’t the end of the story. Diabetes just isn’t that simple. For a long time, we thought of the condition as being either “childhood-onset” or “adult-onset”, and this is how many people still think of the disease. Yet in the last decade, this thinking was discredited as it was that adults in their 40s and 50s could develop a form of the disease that looked very “childhood”-like, while .
It is also quite likely that the risks and outcomes of diabetes will look different in people who live outside Sweden and Finland, such as in the Middle East, whose nations have some of the highest rates of the condition in the world. The results can’t even be generalised to the rest of Europe, as those living in southern Europe are likely to have very different diets and lifestyles.
That’s not to pour cold water over the study – it is an important first step. And even if it is too soon for doctors to use the subtypes for diagnosis, the blood test, if verified, could assist with prescriptions.
“I wouldn’t necessarily tell patients [about the new set of subtypes] – I’d just use it to tweak treatments,” says  at McGill University in Canada, who wasn’t involved in the study. He stresses that our understanding of diabetes and other metabolic diseases is still very much evolving. “This is not a quick discovery – it’s a 20-year plan.”
The Lancet Diabetes & Endocrinology
