Things just got a lot more complicated than type 2 diabetes vs type 1. But changes in how these diseases are defined are likely to help those who suffer from them

Have you ever heard of type 5 diabetes? How about types 3 or 4?

If you’re like most people, even those who happen to suffer from diabetes, you’ve likely only ever heard of type 1 and type 2. But a new study out of Scandinavia aims to rewrite everything we know about these two diseases.

Namely, that there are actually five of them.

 By looking at a number of metrics, including A1C, age of diagnosis, insulin resistance, BMI, and the presence of autoantibodies, the Swedish and Finnish scientists were able to categorize the diabetics they looked at into five distinct “clusters.” These clusters, they argue, represent five different diseases, each requiring a specific treatment.

Cluster 1: Severe Autoimmune Diabetes

The first cluster and the one that made up the smallest number of patients has been dubbed “severe autoimmune diabetes.” All subjects that fell into this cluster were found to have diabetes-related autoantibodies that suggest their low insulin levels are caused by an autoimmune factor. This cluster not only includes all traditional type 1 diabetics but also anyone diagnosed with latent autoimmune diabetes in adults (LADA).

Cluster 2: Severe Insulin-Deficient Diabetes

While this cluster appears similar to cluster 1 in that most patients were younger at the time of diagnosis and are insulin deficient, none of these patients had diabetes-related autoantibodies. Patients in this cluster were also found to have a higher rate of retinopathy compared to the other groups.

Cluster 3: Severe insulin-resistant Diabetes

Patients in this cluster were identified as having a high degree of insulin resistance and high body mass indexes. Those that fell into this cluster were also much more likely to suffer from kidney disease than any other cluster.

Cluster 4: Mild Obesity-Related Diabetes

This cluster was also made up of individuals with higher BMIs, but these patients did not show insulin resistance. Like all diabetics, their blood sugar was elevated, but the cause appeared to be metabolic in origin, not due to insulin deficiency or resistance.

Cluster 5: Mild Age-Related Diabetes

The final cluster contained the highest number of patients. Most of them were elderly but not obese. Their symptoms, like those in cluster 4, were milder than the other clusters and were not caused by severe insulin resistance or deficiency.

Why “Diabetes Type 2 vs Type 1” Isn’t Good Enough

While it may seem like an unnecessary distinction, breaking diabetes into five separate diseases could have a profound impact on the prognosis for every diabetic.

Today, we know that type 1 diabetes (cluster 1) must be treated with multiple daily injections of insulin or an insulin pump. This treatment is very specific to the cause of the disease.

The majority of type 2 diabetics receive a treatment that consists of oral medications to reduce insulin resistance and lower blood sugars. They are also told to follow a certain diet and exercise more. But what if that treatment plan only actually works for some causes of type 2 diabetes?

According to the five cluster theory, there are four different causes of what is typically thought of as type 2 diabetes (clusters 2 through 5). Rates of secondary complications seen in each cluster already tell us that this “typical” treatment isn’t right for every cause. Clusters 2 and 3 both suffer complications at a higher rate than cluster 1 (which already gets a specialized treatment) and clusters 4 and 5, which would appear better suited to treatment by current means.

If you’ve ever felt like you do everything you’re told but still struggle to get your blood sugar under control, this theory might explain why. And also why you’re not alone in feeling that way.

Don’t Bank on New Treatments Yet

Unfortunately, there is still a lot of research that needs to be done before you can expect the medical community to implement any changes in response to this finding.

This specific study only looked at diabetics of Scandinavian descent. Broader studies looking at populations with wider ethnic variation may very well find that there are seven or eight distinct diabetic clusters out there. And once all clusters are identified, the medical community would still need a reliable way to test for each of them.

As all types of diabetes are widely affected by genetic and environmental components, designing one test to identify the cause and subsequent treatment for every patient seems unlikely. 

But if you’ve seen little improvement in your numbers with current treatment methods, this study should offer you some hope. It provides strong evidence that the problem isn’t you. It’s that your type 2 diabetes is different than the type 2 diabetes the treatment was intended for.