What is Type 1.5 Diabetes?

Could your diagnosis of type 2 diabetes be a different form of diabetes? Latent Autoimmune Diabetes in Adults (LADA), commonly referred to as type 1.5 diabetes, is considered a subcategory of type 1 diabetes that is commonly misdiagnosed as type 2 diabetes.^1,2 According to a journal article from Diabetic Medicine, “around 4-14 % of patients classified with type 2 diabetes have DAA” (diabetes associated antibodies characteristic of LADA).¹

As awareness of this form of diabetes grows, diagnosis is becoming more common, and it is suspected that LADA “is prevalent and likely far more prevalent than childhood onset type 1 diabetes.”¹

What is 1.5 diabetes (LADA)?

There has yet to be consistent definition of LADA which has made diagnosis of LADA less common. Features of LADA include:

• Adult onset, with diagnosis occurring at age 30 or older
• Presence of at least one of the diabetes associated antibodies²
  • The most commonly found antibody is: glutamic acid decarboxylase (GAD)²
• Insulin is often not needed for a period of time after diagnosis^1,2
  • Loss of beta cell (insulin producing cells in the pancreas) function is more gradual than in childhood onset type 1 diabetes²
• C-peptide (a marker of insulin production) level may be low or normal
  • Type 2 diabetes: C-peptide is normal to high
  • Type 1 diabetes: C-peptide is very low²
• Patients with LADA often have a more favorable metabolic profile in comparison to those with type 2 diabetes
  • Lower triglyceride level, higher HDL level, lower BMI (body mass index), and lower blood pressure¹

Risks of misdiagnosing 1.5 diabetes (LADA)

• “Correctly diagnosing LADA is essential to choosing a proper treatment regimen that will attain and maintain glycemic control.”²
• Improved diagnosis of LADA allows for such patients to hopefully have closer follow-up with their physician thus allowing for earlier identification of metabolic decompensation and need for insulin initiation (instead of trying multiple oral medications and delaying the ultimate need for insulin).¹

Risk of long term complications and co-morbidities

• Prevalence of neuropathy, retinopathy, neuropathy is comparable to what is seen in those with type 2 diabetes¹
• Research thus far has not indicated that patients diagnosed with LADA have a lower risk of cardiovascular disease, peripheral arterial disease, or stroke, despite typically having a healthier metabolic profile.¹
• Patients diagnosed with LADA have a higher prevalence of other autoimmune diseases, in particular thyroid disease. Correct diagnosis therefore allows for more timely screening and treatment.¹

Treatment for 1.5 diabetes (LADA)

• “…patients with LADA should be treated with insulin as a first choice when glycemic control deteriorates…”¹
• Other classes of diabetes medications that are being researched for their use in LADA:
  • Treatments that may preserve beta cell function: dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) receptor agonists^1,2

Oral diabetes medication that should not be used for treatment of LADA:

• Sulfonylureas should not be used in the treatment of LADA as this class of medication will increase the rate of c-peptide deterioration.^1,2

If you are concerned and feel that you may have been misdiagnosed, please speak with your physician to discuss if further testing (i.e. c-peptide levels and/or antibody testing) is indicated.