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How Many Types of Diabetes Are There? Two? Five? Or Eleven?

Mar 17, 2018

More specific classifications for the disease could lead to more personalized treatments in the future. Is it time?  

Diabetes is normally split into two categories: type 1 and type 2. But a group of scientists from Sweden and Finland say diabetes is actually five separate diseases. More specific classifications for the disease could lead to more personalized treatments in the future. Knowing which of these 5 categories of diabetes your patients have can be a benefit in choosing the treatment.

We know that each of the five proposed categories are genetically distinct. Their signs and symptoms can vary by age, weight, insulin resistance, how much insulin they can produce, or if the diabetes is caused by an autoimmune disorder.

This new classification of diabetes can be the first step toward personalized treatment of diabetes. Existing treatment guidelines are limited by the fact they respond to poor metabolic control when it has developed, but do not have the means to predict which patients will need intensified treatment.

This study moves us toward a more clinically useful diagnosis, and represents an important step toward personalized treatment of diabetes as our current diagnostics and classification of diabetes are unable to predict future complications or choice of treatments. We know that diabetes is a progressive disease and the type of diabetes changes as a person gets older, which means that the patient will need probably need new drugs that work differently.

Currently the way we determine a treatment for type 2 diabetes is a one-size-fits-all algorithm. We start a patient with metformin and then if that doesn’t get the patient to goal, other drugs are added. But recognizing that there are 5 types of diabetes and not just 2 types will help us to prescribe a treatment that is more specific to the patient’s type of diabetes.

The five types of diabetes include:

  • 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 did not have excessive weight. 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 at diagnosis and did not have excessive weight. They were also not producing much insulin. But, crucially, their immune system was not the cause of their disease. People in this cluster “looked for all the world like [they had] type 1” diabetes, but 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 had excessive weight 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 have obesity.
  • 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.

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, another complication of diabetes that can cause vision loss.

Clusters 2 and 3 are both severe forms of diabetes that were “masked within type 2 diabetes,” the researchers said. People in these clusters may benefit from aggressive treatment to prevent diabetes complications, the authors said.

Maybe it is time to make the change to categorizing diabetes more accurately. See Dr. Schwartz’ recommendation to changing it from 2 to 11 types.

Dr. Stanley Schwartz Part 1, New Diabetes Classification
Dr. Stanley Schwartz Part 2, Benefits of Early Combination Therapy
Dr. Stanley Schwartz Part 3, Using Evidence-Based Practice
Dr. Stanley Schwartz Part 4, Conference Anticipations

Also see: The New Diabetes Classification by Stanley Schwartz, MD

Practice Pearls:

  • This new classification could provide a powerful tool to individualize treatment regimens and identify individuals with increased risk of complications at diagnosis.
  • Categorizing diabetes into 5 different clusters will make it more successful in individualizing treatments.
  • This is a way to possibly prevent future complications from diabetes and truly individualize treatments.


The Lancet March 2018  DOI: https://doi.org/10.1016/S2213-8587(18)30051-2