It Happened to Me: Type 1 Diabetes in Adults is Often Misdiagnosed as Type 2


I was misdiagnosed with gestational and type 2 diabetes before getting the correct diagnosis of type 1 (LADA). I’ve heard the same story from many others. And a newly publicized report in Diabetologica puts out some statistics on this all too common mistake. Below is the press release that details the study:

New research presented at this year’s annual meeting of the European Association for the Study of Diabetes (EASD) reveals that many cases of type 1 diabetes (T1D) diagnosed after the age of 30 are not being properly identified and are frequently misdiagnosed as being type 2 diabetes (T2D), potentially leading to delays in receiving appropriate treatment.

UK Prime Minister Theresa May is a high-profile example of someone who was initially thought to have T2D, only to later return to her doctors when the medications for T2D did not work. She was subsequently diagnosed with T1D. (see link below)

This new research conducted by Dr Nick Thomas and colleagues at the University of Exeter, Exeter, UK sought to determine the prevalence and characteristics of T1D occurring after the age of 30 in patients with insulin-treated diabetes.

T1D is characterised by the rapid and severe loss of insulin production as the cells in the pancreas which produce the hormone are attacked and destroyed by the body’s own immune system Individuals with the disease lose the ability to make their own insulin and therefore require regular doses of insulin to control their blood glucose, either in the form of injections or via a pump, and unlike many people with T2D, cannot manage their condition through diet, exercise and blood sugar monitoring alone.

The researchers characterised T1D as being the rapid onset of insulin dependence within 3 years of initial diagnosis, together with a severe deficiency of insulin production by the pancreas. They analysed a population cohort of 583 individuals who had insulin-treated diabetes that had been diagnosed after the age of 30. The characteristics of their disease were compared with other participants who still produced some insulin, as well as with 220 individuals with severe insulin deficiency that was diagnosed before the age of 30.

The study found that 21% of those with insulin-treated diabetes who were diagnosed after the age of 30 had severe insulin deficiency, confirming Type 1 diabetes. Out of this group, 39% did not receive insulin when they were initially diagnosed, with 46% of those individuals self-reporting that they had T2D. A rapid progression to insulin dependence was highly predictive of late-onset T1D with 84% of those with the disease requiring insulin within just one year.

Among participants who became insulin dependent within 3 years, 44% developed a severe deficiency of their body’s own insulin. Their clinical, biochemical, and genetic characteristics were found to be comparable to those of participants who had been diagnosed before the age of 30. In contrast, patients who retained some insulin production had substantially lower T1D genetic risk scores, antibody positivity (linked to the immune response that damages pancreatic cells), and a higher body mass index (BMI).

Where insulin treatment had been delayed, the patients were found to be on average older (48 years vs 41 years for those who received insulin immediately), and only 50% had self-reported as having T1D, compared to 96% of individuals who had been given insulin upon initial diagnosis. These patients were also much more likely (29% vs 7%) to have been given oral hypoglycaemic drugs in an attempt to control their disease.

Dr Thomas says: “Type 1 diabetes leading to severe insulin deficiency has similar clinical and biological characteristics to that occurring at younger ages, but is frequently not identified.”

He adds: “Clinicians should be aware that the majority of patients needing insulin within 3 years of diagnosis will have Type 1 diabetes, even if they were initially thought to have type 2 diabetes and did not need insulin at diagnosis. Getting the right diagnosis is important for these patients to receive the right education and treatment.”

Notify of
oldest most voted
Inline Feedbacks
View all comments
4 years ago

My mom was DX at 52 as a type 2. Lost a bunch of weight. Then she told the doctor she had a grandson with type 1. Then they tested her for type 1. Sure enough she has type 1.

kristina blake
kristina blake
4 years ago

I was 30 years olds, no risk factors for T2 (especially the no family history one), I was recently retired as a professional ballet dancer – so very active, weighed less than 110 lbs (I’m 5’6″)as a working weight, was close to 100 lbs when I went to see a doctor. I had the classic symptoms of T1 – in fact it was the constant peeing and I was so dehydrated that my tongue was cracked – that drove me to see an HCP. I was sent home with advice to watch my weight, and watch my diet. Since there… Read more »

Janis Reed
Janis Reed
4 years ago

I am another of the mis-diagnosed. In 2005 after being followed as having “impaired fasting glucose”, my doctor told me that I was Type 2 and would never have to go on insulin. After a multitude of T2D drugs and several years of delay in going on insulin, I finally started insulin about 5 years ago, obviously later than I should have. Last year I paid to have the GAD test done to confirm my T1D diagnosis. I am on the Libre system as is Teresa May and use Fiasp and Tresiba insulins. I even attended my very first ever… Read more »

Copyright © 2009-2021 Diabetes Media Foundation, All Rights Reserved.
ASweetLife™ is a trademark of the Diabetes Media Foundation, All Rights Reserved.
Would love your thoughts, please comment.x