Type 1 diabetes (diabetes mellitus) is an autoimmune condition that most often develops quickly in children. In Type 1 diabetes, antibodies destroy pancreatic cells, impairing the ability to produce insulin. Insulin is necessary to move sugar (glucose) out of the bloodstream and into your cells to provide energy. The treatment for Type 1 diabetes is insulin therapy.
Type 2 diabetes differs in that while you are still able to produce insulin, the insulin is not effective at moving sugar out of your bloodstream. The treatment for Type 2 diabetes includes medications that make insulin more effective, as well as dietary and lifestyle changes.
A lesser-known sub-type of diabetes has been getting more attention recently. Latent autoimmune diabetes of adults (LADA) – also referred to as type 1.5 diabetes – falls under the umbrella of type 1 diabetes. LADA, however, usually develops slowly during adulthood. LADA also does not typically require insulin therapy until months or years after the initial onset of the disease.
The name “Type 1.5” is sometimes used because LADA has features of both Type 1 and Type 2 diabetes.
- Like Type 1 diabetes, LADA is characterized by the presence of antibodies that destroy pancreatic cells and impair insulin production
- Like Type 1 diabetes, C-peptide levels are low in LADA
- Like Type 1 diabetes, insulin therapy is eventually needed for LADA (though the need for insulin develops more slowly)
- Like Type 2 diabetes, diagnosis of LADA occurs most often in adulthood
- Like Type 2 diabetes, some degree of insulin resistance is common in LADA
Are you at risk of LADA?
You are at greater risk of developing LADA if:
- You have a family or personal history of autoimmune disease
- You are female (females, in general, have a greater risk of autoimmune diseases, including diabetes)
- You are over the age of 30
- You already have a diagnosis of type 2 diabetes
- You have autoimmune thyroid disease. (Patients with LADA, compared with those with Type 2 diabetes, are more likely to have other autoimmune diseases, especially autoimmune thyroid disease.)
Signs and symptoms of LADA / Type 1.5 diabetes
Do you have any of the following common signs and symptoms of LADA / Type 1.5 diabetes?
- You feel excessively thirsty
- You urinate frequently and have a high volume of urine
- You have disturbances in your vision, especially blurriness
- You are losing weight, in some cases rapidly
- You feel excessively hungry, even after eating
- You feel fatigued
- You have tingling or numbness in your feet and/or hands
- Your cuts and bruises are slow to heal
Clinical signs of LADA include:
- You have elevated blood sugar (fasting glucose)
- You have an elevated hemoglobin A1C level
- You are underweight, of normal weight, or slightly overweight
How is LADA / Type 1.5 diabetes diagnosed?
Your diagnosis of LADA can be confirmed by the following tests:
- A blood sugar/fasting glucose level of 126 mg/dL or higher
- A hemoglobin A1C level of 6.5% or higher
- A 2-hour glucose tolerance test (GTT) glucose test result of 200 mg/dL or higher
- Low or low-normal C-Peptide levels
- Elevation of at least one of several types of autoantibodies, including:
o Antibodies to glutamic acid decarboxylase (known as anti-GAD antibodies, or GADAs), which are the most common antibodies in LADA
o Antibodies to Islet Cell Antigens (anti-ICA)
o Antibodies to tyrosine phosphatase proteins (IA-2s)
o Antibodies to insulin
Treatment of LADA/Type 1.5 Diabetes
According to current guidelines, doctors should manage LADA with type 2 diabetes drugs and recommended dietary changes for six months after diagnosis. These medications can include:
- Metformin (Glucophage) – Metformin as a stand-alone therapy has, however, not yet been studied for use in LADA
- Dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) like sitagliptin (Januvia), linagliptin (Tradjenta), and saxagliptin (Onglyza).
- Glucagon-like peptide 1 receptor agonists, including exenatide (Byetta/Bydureon), liraglutide (Victoza, Saxenda), lixisenatide (Lyxumia), albiglutide (Tanzeum), dulaglutide (Trulicity), and semaglutide (Ozempic).
- Thiazolidinediones (TZD drugs), including pioglitazone (Actos) and rosiglitazone (Avandia)
An exception: type 2 diabetes drugs called sulfonylureas are not used as a first-line treatment for LADA because they tend to damage beta cells and worsen glucose control in LADA patients. These drugs include chlorpropamide (Diabinese), glimepiride (Amaryl), glyburide (Glynase), glipizide (Glucotrol), glyburide (DiaBeta), glipizide (GlipiZIDE), and tolazamide (Tolinase).
Over time, however, as beta cell destruction continues, LADA eventually requires insulin therapy, usually from 6 months to 5 years after the initial diagnosis.
Should insulin be started right away?
While the guidelines recommend holding off on starting insulin therapy for LADA, this guidance is increasingly controversial. Some experts are now saying that starting insulin treatment as soon as a diagnosis of LADA is made may help reduce the risk of a significant, life-threatening condition called diabetic ketoacidosis, as well as complications of elevated blood sugar such as vision impairment, nerve damage, or kidney problems.
Can the progress of LADA be slowed?
Experts are now identifying the potential benefit of treating LADA with DPP-4 inhibitors, glucagon-like peptide 1 receptor agonists, TZD drugs, and vitamin D. The goal is to help preserve beta cell function and slow the progression of LADA and potentially achieve a remission.
Ideally, the earlier these types of therapies can be started, the more likely they are to have benefits. A recent research study, in fact, actually found that in some patients with LADA, antibodies may be normalized and blood glucose control achieved –in some cases without insulin therapy – after several months of treatment with sitagliptin (Januvia) along with vitamin D.
Is your Type 2 diabetes actually LADA?
Experts believe that, on average, around 10 percent of adults diagnosed with Type 2 diabetes have LADA. This number is higher – 25 percent – among those under age 35 diagnosed with Type 2 diabetes. Some researchers have suggested that as many as 50 percent of those who are underweight or of normal weight with a Type 2 diabetes diagnosis may, in fact, have LADA.
This means that if you have a diagnosis of Type 2 diabetes, you may actually have undiagnosed LADA. If that is the case, you may need insulin therapy, but only receive it after months – or years – of poor response to type 2 diabetes drugs, changes to diet, and exercise, and an increased risk of complications due to chronically elevated blood sugar levels.
Given this situation, some experts recommend that everyone with Type 2 diabetes have antibody screening to identify LADA. This recommendation is controversial, however, and general screening is not yet standard medical practice.
If you have been diagnosed with type 2 diabetes, but have any of the following factors, you should ask about antibody screening for LADA:
- You are underweight or normal weight
- You have a personal or family history of autoimmune disease and/or thyroid disease
- You are unable to achieve good glucose control (elevated blood sugar levels, or high hemoglobin A1C levels) despite treatment with drugs for type 2 diabetes and dietary and lifestyle changes