What is Type 1.5 Diabetes?
Last updated: March 2022
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 diagnosis1,2
- 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:
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.
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