Type 5 Diabetes: What Formal Recognition Means‍

Type 5 diabetes, also known as Severe Insulin-Deficient Diabetes (SIDD), is a subtype of type 2 diabetes. It is typically diagnosed in individuals with a low body mass index (BMI), among other key diagnostic criteria. 

The formal recognition of SIDD marks a significant milestone in the evolution of diabetes care. This working group’s efforts could help establish a new standard for diabetes testing and diagnosis.

How Do SIDD and MODY Differ?

Before discussing what this formalization and working group potentially means for diabetes research and testing, it’s crucial to understand SIDD. Sometimes confused with MODY (Maturity Onset Diabetes of the Young), SIDD is a different state of diabetes marked by specific symptoms and characteristics.

What is MODY?

While millions are affected worldwide, MODY is still considered a rare form of diabetes. It is typically hereditary, passed down from a parent with a gene mutation. A scientific report from August of 2023 states that MODY is explicitly caused by pancreatic islet cell development defects impairing insulin secretion. 

People with MODY generally have heterozygous mutations. If a parent carries this mutation, each of their children has a 50 percent chance of inheriting it by age 25.

MODY typically develops in adolescence or early adulthood, accounting for only five percent of all U.S. cases. Like other types of diabetes, MODY limits the body’s ability to produce insulin, causing high blood sugar levels that can damage the body over time.

According to Diabetes UK, current testing for MODY includes having blood taken for pancreatic antibodies and blood or urine tested for C-peptide. It also includes having blood taken for genetic testing. Both tests can typically be performed in a doctor's office or hospital setting, and then routed to the right specialist for results.

Because it is so rare, doctors may not be aware of it. MODY typically occurs in people under 25, and those with it may not need insulin. Some people with MODY can manage it with exercise and nutrition. 

What is SIDD?

According to a 2020 diabetes journal issued by the American Diabetes Association (ADA), SIDD is defined by clinical clusters based on specific clinical features and genetic associations. VeryWell Health stated that SIDD is likely caused by genetics and behavioral factors, including obesity, inactivity, increased belly fat, and insulin resistance.

People diagnosed with SIDD typically have a BMI below 25, low insulin secretion, poor metabolic health, and high hemoglobin A1C (HbA1c) levels. 

Practitioners use six data points to determine a diagnosis of SIDD, including BMI, age at diagnosis, HbA1c level, beta-cell function, insulin resistance, and diabetes-related autoantibodies. Once diagnosed, treatment for SIDD may include diet and lifestyle changes and medications like metformin or insulin. 

What is Type 2 Diabetes?

Because both types of diabetes are linked to type 2 in the general media, it’s also important to understand what type 2 diabetes (T2D) means in this context. 

Type 2 diabetes is the most common form of diabetes, accounting for 90 to 95 percent of all new cases. People with type 2 may still produce insulin, whereas people with type 1 and type 1.5, LADA (Latent Autoimmune Diabetes in Adults), do not. 

Being overweight and inactive are risk factors for T2D. Family history, age, and race are also factors in the development of T2D.

Simplifying the Different Diabetes Types

Simply put, according to a 2020 diabetes journal issued by the American Diabetes Association (ADA), the main difference between MODY and SIDD is that MODY is recognized as a monogenic form of diabetes, while SIDD is recognized as a subtype of type 2 diabetes.

Other forms of diabetes include:

• Type 1 diabetes
• Type 2 diabetes
• Type 1.5 diabetes (LADA)
• Monogenic diabetes
• Neonatal diabetes
• Type 3c diabetes
• Gestational diabetes

Type 1 and type 2 diabetes are the most common and well-known forms of diabetes, but there are other types that, while less publicized, are equally important for those affected. Comprehensive testing is essential to accurately identify an individual's type of diabetes. However, such testing is not always accessible, especially in rural areas where quality healthcare resources and tools may be limited. 

This lack of access contributes to the frequent misdiagnosis of diabetes, as many people around the world do not have guaranteed access to proper testing and care. To illustrate the issue, it is estimated that more than 30 percent of all new Type 1 diabetes cases are misclassified as Type 2 diabetes. 

Due to limited research and challenges related to healthcare access and affordability, there is still much to learn about the various subtypes of diabetes. Improved understanding and diagnosis of these subtypes could lead to a significant reduction in misdiagnoses over time.

Misdiagnoses Aren’t Uncommon for Many Reasons

While types vary, there are four common warning signs that each of them encompasses, known as the four T’s:

• Toilet: Frequent urination is common among individuals with high blood sugar levels. Glucose is lost in the urine, causing dehydration. Frequent urination is common, particularly at night.
• Thirst: People experience excessive thirst and are constantly craving drinks.
• Thinner: People may experience unexplained weight loss or muscle loss. Without insulin, your body breaks down its fat and muscle
• ‍Tired: Individuals become exhausted, lacking energy, with only the desire to sleep.

While diagnoses may seem straightforward since type 1 and type 2 are the most prevalent types, identifying the other types listed above can help inform individuals’ diagnosis and treatment journeys, leading to care plans that are better tailored to their bodies and needs.

This is truly what makes the formalization of type 5 diabetes so pivotal.

How Will Formalizing Type 5 Diabetes Improve Health Outcomes?

Formalizing recognition for type 5 diabetes may help reduce misdiagnoses and lead to more personalized care. Because type 5 diabetes has such a distinct metabolic profile, diagnosing it correctly may help people with type 5 diabetes treat it more effectively, especially in low-resourced regions where the IDF says it is most prevalent.

Cost-effective approaches will be crucial for those diagnosed. 

Reflecting on this milestone in the evolution of diabetes research and care, IDF President, Professor Schwarz, said, “The recognition of type 5 diabetes marks a historic shift in how we approach diabetes globally. For too long, this condition has gone unrecognized, affecting millions of people and depriving them of access to adapted care.”

Tailored care improves health outcomes for people with chronic illnesses like diabetes. The working group will take “decisive steps” to ensure this, emphasizing equity, science, and saving lives.

Read IDF’s full announcement and learn more about the working group’s early efforts and goals.