If you've been diagnosed with Type 2 diabetes but your treatment isn't working as expected, you might actually have a different condition. Type 1.5 diabetes, also known as LADA (latent autoimmune diabetes in adults), is an autoimmune form of diabetes that has similarities to Type 1 and Type 2 diabetes.
What is Type 1.5 diabetes, and how do you know if you have it? Kathleen Estrada, M.D., an endocrinologist at Henry Ford Health, explains.
What Is Type 1.5 Diabetes?
Type 1.5 diabetes is essentially Type 1 diabetes that develops in adulthood. Like Type 1 diabetes, it's an autoimmune condition in which your body’s immune system attacks insulin-producing cells in the pancreas. However, unlike typical childhood Type 1 diabetes, Type 1.5 develops slowly, sometimes over years.
This slower progression makes Type 1.5 diabetes tricky to diagnose. You may initially do well with Type 2 diabetes medications or lifestyle changes. But over time, as your pancreas loses its ability to make insulin, it gets harder to control your blood sugar.
“Type 1.5 diabetes often looks more like Type 2 diabetes initially,” says Dr. Estrada. “Someone may have features of Type 2, like obesity or insulin resistance, but their body is actually attacking the pancreas, like in Type 1 diabetes.”
Why Type 1.5 Diabetes Gets Misdiagnosed
Why is Type 1.5 diabetes so confusing? Several factors may lead to misdiagnosis, including:
- Age of onset: Type 1 diabetes is often considered a childhood disease. So when adults develop diabetes, Type 2 is usually the first assumption.
- Insulin resistance: Many people with Type 1.5 diabetes also have insulin resistance or obesity, which are common in people with Type 2 diabetes.
- Gradual progression: Because the damage to your pancreas cells happens slowly, Type 2 diabetes medications may work, at least for a while.
Red Flags That Suggest Type 1.5 Diabetes
How would you know if you have Type 1.5 diabetes? Only testing can tell. If you have these warning signs, talk with your provider about screening:
- Rapid deterioration: Your A1C suddenly jumps quickly and significantly (for example, from 7% to 12%).
- Healthy BMI range: You don’t carry extra weight.
- High insulin requirements: You need both long-acting and mealtime insulin consistently.
- Lack of response to standard treatments: Oral medications and lifestyle changes aren't controlling the condition.
- Family history: You have a first-degree relative with Type 1 diabetes.
- Recent COVID-19 infection: Type 1.5 may occur after COVID-19 in some people, though more research is needed.
How Doctors Diagnose Type 1.5 Diabetes
If your doctor suspects you have Type 1.5 diabetes, they'll order specific blood tests, including:
- Antibody testing: The most common test looks for GAD-65 antibodies, which attack the pancreas. If these antibodies are present at significant levels, it means you have an autoimmune form of diabetes.
- C-peptide test: This measures how much insulin your body is still producing. “The C-peptide test gives us a sense of how much insulin reserve you have, since the autoimmune process can be very slow,” Dr. Estrada explains.
Why the Correct Diagnosis Matters
Getting the right diagnosis is important for your treatment, which will likely include:
- Insulin needs: People with Type 1.5 diabetes eventually need insulin and cannot safely stop taking it.
- Risk of diabetic ketoacidosis (DKA): Without insulin, people with Type 1.5 can develop DKA, a life-threatening condition.
- Realistic expectations: Understanding you have an autoimmune condition helps you and your provider set the right goals for blood sugar control.
Managing Type 1.5 Diabetes
Once you have a diagnosis, you may need:
- Glucose checks: The standard finger pricks or a continuous glucose monitor (CGM) can alert you to highs and lows in your blood sugar levels.
- Insulin therapy: Most people with Type 1.5 diabetes need long-acting (basal) insulin for steady background coverage and rapid-acting (mealtime) insulin to cover the rise in blood sugar from eating.
- Non-insulin medications: Because many people with Type 1.5 diabetes also have insulin resistance, additional medications may help. “Sometimes we will add metformin to someone with Type 1 or Type 1.5 diabetes because they also have insulin resistance,” Dr. Estrada says.
Lifestyle Still Matters
“A healthy diet and lifestyle are still very important if you have Type 1.5 diabetes,” Dr. Estrada says. “If you consume more carbs and sugar and have excess weight, it’s harder to manage the condition.” Maintaining a healthy weight, eating a balanced diet and staying physically active can reduce insulin requirements, improve blood sugar control and lower the risk of complications.”
Living Well With Type 1.5 Diabetes
It can be overwhelming to get this new diagnosis, but remember that you can live a healthy life with Type 1.5 diabetes. “All those serious complications you hear about never have to happen,” Dr. Estrada says. “The most important thing is to get good blood sugar control as much as possible to lower the chances of those complications.”
Good control—not perfection—is the goal. “Highs and lows are part of diabetes,” Dr. Estrada says. “If you want to enjoy that birthday cake, do it. Just give yourself some insulin. You might go a little high, but if it was worth it, that's okay. Make treats an occasional thing, not an everyday thing.”
Advocate for Yourself
If you've been diagnosed with Type 2 diabetes but something doesn't feel right, speak up. “If patients feel like something seems like it's not lining up, have that conversation with your doctor,” Dr. Estrada advises.
Reviewed by Kathleen Estrada, M.D., an endocrinologist who sees patients at Henry Ford Medical Center – Columbus and Henry Ford Medical Center – New Center One.
