Does Type 2 diabetes really exist?

The term "Type 2 diabetes" is leading medical researchers astray, and resulting in sub-optimal treatment for patients, says a leading diabetes expert in a Viewpoint published in the Lancet.

According to Professor Edwin Gale, of Southmead Hospital, Bristol, UK, applying the term 'Type 2 diabetes' to the complex and varied set of symptoms experienced by people with the condition is what logicians call a category error, when a problem is assigned to a category inappropriate to its solution.

Speaking to Lancet TV, Professor Gale said, "If you give something a name, you imply an entity; you imply that this thing actually exists. In practice, when somebody like myself talks about Type 2 diabetes, I'm saying 'a form of diabetes for which I can find no other cause'. In other words, it's a diagnosis of exclusion…There are various conditions, spectrums, and severities of diseases, all wrapped into this one definition."

Clinicians diagnose Type 2 diabetes when a patient's body can no longer produce enough insulin, or when the insulin that is produced doesn't work properly, which leads to problems maintaining a normal blood glucose level. According to Diabetes UK, Type 2 diabetes is estimated to affect around 2.6 million people in the UK [1].

However, Professor Gale argues that because the symptoms referred to by the term 'Type 2 diabetes' have such widely varying causes, mechanisms, and treatments, the term is misleading both researchers and patients.

Treating Type 2 diabetes as a single disease has "has caused the work of generations of young investigators to be wasted in pursuit of indefinable entities", writes Professor Gale, adding that it has also led to a failure to achieve satisfactory treatment and risk management for many patients, "reinforced by the introduction of one-size-fits-all guidelines for disease management."

Although Professor Gale predicts that "the ghostly entity of type 2 diabetes is likely to haunt us for years to come", as an interim solution, he proposes replacing 'Type 2 diabetes' with the term 'idiopathic hyperglycaemia' [2], which would encourage clinicians to stop thinking about the condition as a disease in its own right, but rather as an outcome of many interacting processes. These processes vary from person to person, argues Professor Gale, and therefore so should treatment.

"A problem that cannot be defined in scientific terms cannot have a scientific solution," Professor Gale writes. "When a century of scientific endeavour brings us round to the conclusion that we cannot define what we are talking about, it might be time to consider adjusting our minds. It is widely appreciated that type 2 diabetes is not a uniform disease entity with a definable cause, mechanism, and treatment, so why are these terms always used?"