Scientists unveiled a revised classification for diabetes mellitus, one they said could lead to better treatments and help doctors more accurately predict life-threatening complications from the disease.
There are five distinct types of diabetes that can occur in adulthood, rather than the two currently recognised, they reported in The Lancet Diabetes & Endocrinology
The findings are consistent with the growing trend toward “precision medicine”, which takes into account differences between individuals in managing the disease. In the same way that a patient requiring a transfusion must receive the right blood type, diabetes sub-types need different treatments, the study suggested.
Similarly, scientists have also identified distinct kinds of the microbiome — the bacterial ecosystem in our digestive tract — that can react differently to the same medication, rendering it more or less effective.
People with diabetes mellitus have excessively high blood glucose, or blood sugar, which comes from food.
Some 420 million people around the world today suffer from diabetes, with the number expected to rise to 629 million by 2045, according to the International Diabetes Federation.
Currently, the disease is divided into two sub-types.
With type-1 — generally diagnosed in childhood and accounting for about 10% of cases — the body simply doesn’t make insulin, a hormone that helps regulate blood sugar levels. It is also called Insulin Dependent Diabetes Mellitus(IDDM) as the only treatment is insulin injection.
For type-2, the body makes some insulin but not enough, which means glucose stays in the blood. This is also known as Non-Insulin Dependent Diabetes Mellitus(NIDDM).
This form of the disease correlates highly with obesity and can, over time, lead to blindness, kidney damage, and heart disease or stroke.
It has long been known that type-2 diabetes is highly variable, but classification has remained unchanged for decades. For the study, researchers monitored 13,270 newly diagnosed diabetes patients ranging in age from 18 to 97.
By isolating measurements of insulin resistance, insulin secretion, blood sugar levels, age, and the onset of illness, they distinguished five distinct clusters of the disease — three serious and two milder forms.
This is not changing the diagnosis or the terminology for the diagnosis, It’s just providing a way to classify the diagnosis of type 1 and type 2.
The clusters were:
• Cluster 1: Called “severe autoimmune diabetes,” this form is similar to type 1 diabetes. People in this cluster were relatively young when they were diagnosed, and they were not overweight. They had an immune system (autoimmune) disease that prevented them from producing insulin.
• Cluster 2: Called “severe insulin-deficient diabetes,” this form was similar to cluster 1 — people were relatively young and not overweight and were also not producing much insulin. But, crucially, their immune system was not the cause because they didn’t have “autoantibodies” that indicate type 1. Researchers aren’t sure why this happens, but people in this group may have a deficiency in the cells that produce insulin.
• Cluster 3: Called “severe insulin-resistant diabetes,” this form occurred in people who were overweight and had high insulin resistance, meaning their bodies were making insulin, but their cells were not responding to it.
• Cluster 4: Called “mild obesity-related diabetes,” this form occurred in people who had a milder form of the disease, without as many metabolic problems as those in cluster 3, and they tended to be obese.
• Cluster 5: Called “mild age-related diabetes,” this form was similar to cluster 4, but the people were older at their age of diagnosis. This was the most common form of diabetes, affecting about 40 percent of people in the study.
Clusters 2 and 3 are both severe forms of diabetes that were “masked within type 2 diabetes” till now. People in cluster 3 had the highest risk of kidney disease, a complication of diabetes, while people in cluster 2 had the highest risk of retinopathy.