Swedish and Finnish researchers said there should be five, not just two types of diabetes. The current classifications are type 1 diabetes which a disease of the immune system and type 2 which is a disease of poor lifestyle.
Type 1 diabetes attacks the beta-cells, the insulin factory of the body, which results in insufficient hormones to control blood sugar levels. Type 2 diabetes occurs because of body fat which affects the way insulin works.
Since diabetes is actually five separate diseases, the treatment could be tailored to each of the five types. It could be used in an era of personalized medicine for diabetes patients, BBC reported.
The classification was based on a study made by researchers at Lund University Diabetes Center in Sweden and the Institute for Molecular Medicine Finland. The researchers assessed 14,775 patients, including performing detailed analysis of their blood.
The 8,980 patients were diagnosed with diabetes as adults in a Swedish registry, while another 5,795 patients came from three databases from Sweden and Finland, the Guardian reported.
Based on their analysis, the scientist separated patients into five distinct clusters which they called Clusters 1 to 5.
Patients are considered Cluster 1 or severe autoimmune diabetes, which is the same as type 1 diabetes. The patients are often young, look healthy, but the immune disease resulted in their inability to produce insulin.
Cluster 2 is called severe insulin-deficient diabetes in which patients initially appear to be like those in Cluster 1. Although they are also young and have a healthy weight, they may be strugglnig to produce insulin but their immune system is not at fault.
In Cluster 3, severe insulin-resistant diabetes, the patients are generally overweight and producing insulin. But their body is no longer responding to the hormone
Mild-obesity related diabetes, or Cluster 4, was observed in patients who are very overweight but metabolically closer to normal compared to patients in Cluster 4.
Finally, Cluster 5, or mild age-related diabetes, refers to patients who develop the symptoms when they became significantly older compared to the four clusters. Their version of the chronic ailment tended to be milder.
The reclassification of the disease into five clusters is a real step towards precision medicine, Professor Leif Groop, one of the researchers, said. It will be applied to diagnosis and doctors will target better treatment.
Clusters 1 to 3 patients, who have the severe forms of diabetes, should be treated more aggressively than Clusters 4 and 5 patients. The Cluster 2 patients are those who are now considered type 2 patients since theirs is not an autoimmune disease. The research, however, suggested that the disease of Cluster 2 patients is likely caused by a defect in their beta-cells instead of their being overweight.
The researchers said their treatment should be more closely like the treatment for current type 1 diabetics. They pointed out that Cluster 2 patients have a higher risk of blindness, while it is kidney disease for Cluster 3 patients.
Doctors agree that the current classification of type 1 and type 2 diabetes is not a terribly accurate classification system. Dr. Victoria Salem, a consultant and clinical scientist at Imperial College London, said the five clusters are the future of how they think about diabetes as a disease. But she pointed out that the study will not change the practice today.
She also pointed out that the participants were Scandinavians, while the risk of diabetes considerably varies around the world like the higher risk in South Asians. Salem said that worldwide, there could actually be 500 subgroups, depending on genetics and effects of the local environment. She said the current analysis of five clusters may expand.
Groot, from the Lund University Diabetes Center in Malmo, Sweden and the Folkhalsan Research Center in Helsinki, Finland, said that existing treatment guidelines are limited by the fact that it responds to poor metabolic control when it has developed. However, it does not have the means to predict which patients will need intensified treatment, Medscape reported.
He said the study moves the medical community toward a more clinically useful diagnosis and represents an important step towards precision medicine in diabetes.
Dr. Rob Sladek, from McGill University and Genome Quebec Innovation Center in Montreal, Canada, in an accompanying editorial to the study, published online on March 1 in the Lancet Diabetes & Endocrinology, said that future studies will have to take into account the effect of age on patient outcomes. He added that the other factors excluded in the current analysis may also have an impact.
Sladek said he was not completely surprised that there were up to five clusters of diabetes. He said he is aware of a group of adult-onset patients who are severely insulin deficient. Sladek noted that diabetes is thought as being a balance between insulin needs or insulin resistance from obesity and insulin production. He expects that a couple of the groups would identify patients with insulin resistance.
[researchpaper 리서치페이퍼=Vittorio Hernandez 기자]