Misdiagnosing Type 1 Diabetes

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A recent Australian survey found that 33% of respondents with Type 1 diabetes were wrongly diagnosed with Type 2. Sixty-five percent of them had to go back to the doctor three or more times before they were correctly diagnosed. Why does this happen?

It happens because some doctors assume they know everything when in fact they have no clue. If a person walks in with high blood sugar, they “must” have diabetes. If they’re an adult who never had it before, it “must” be Type 2. End of story.

Actually, both of these conclusions are wrong. Causes of high blood sugar include pancreatitis, kidney or liver disease, infections, and steroid use, among others. And Type 1 can come on at any age. People can also have “Type 1.5,” meaning some other genetic or autoimmune problem that has characteristics of both Type 1 and Type 2 diabetes.

At Diabetes Self-Management, we get a lot of letters from people who have been told they’re Type 2, when they’re probably not. Mary wrote: “I am female, white, 47 [years old], 5′9″ 142 [pounds], a runner, and…recently [diagnosed] with type 2. No one else in my family has diabetes… I have never been obese… Go figure.”

Another commenter wrote: “My mother is 100 lbs soaking wet and has always been extremely active, walking sometimes several miles a day. She was diagnosed with Type 2 about 10 years ago. Her mother, also thin and very active, was also diagnosed with Type 2. Am I missing something?”

Maybe these women do have Type 2. It’s possible. As I wrote about here, there are thin, physically active Type 2s. But there are also millions of people who have late-onset Type 1, or LADA (latent autoimmune diabetes of adults) or MODY (maturity-onset diabetes of the young).

Because they’re not kids, doctors assume these newly diagnosed adults are Type 2. So they don’t give them insulin, even though they are not making enough of their own. Without adequate insulin, it is very hard to control blood glucose, unless you are exercising every waking hour of every day. So these people walk around with high blood glucose for years, making them likely to develop complications, which wouldn’t happen if they were treated correctly.

Emm from New Zealand wrote on Diabetes Forum, “I was 30ish when diagnosed and assumed to be T2. I struggled for around a year — first with strict diet changes, lots of regular exercise, then with pills but nothing was working. Finally an endocrinologist told me in a few seconds flat that I was a type 1. My father had the same story — but even worse. They wouldn’t allow him to start insulin for years. He was in a really bad way by the time they gave him insulin.”

Probably, his doctors blamed him for his high blood sugar levels, for not following their diet or exercising, when what he really needed was insulin. So here’s someone whose father had late-onset Type 1, and even then the doctors wouldn’t evaluate him for Type 1.

Now, you can’t assume someone doesn’t have Type 2, just because they’re thin. Rouhgly15–2 % of people who have Type 2 are thin, although if everyone were diagnosed correctly, that percentage might drop a bit. But it is estimated that 20% of Americans diagnosed with Type 2 may actually have LADA.

Please note that this is not just a concern for thin people. Melitta, who blogs frequently about misdiagnosis of Type 1, says “Many [heavy] people are lumped immediately into the T2 category but actually have Type 1. In my blog I have encouraged several overweight people to work with their doctors to get a correct diagnosis. They all… turned out type 1. In adults, it is easier to spot the misdiagnosed if they are thin, but adult-onset T1 happens to people of all weights.”

The important thing is to know whether your body is producing enough insulin. Doctors can test for this, and if you’re insulin-deficient, they should treat the problem.

The usual tests would be a c-peptide level and/or an insulin level. Each test might cost around $100 or more, so you may have to work with your doc to get them covered or to do it in the most cost-efficient way.

By the way, the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus says we should lose the term LADA, because it’s really just a form of slow-acting Type 1. They’re medical establishment, so I don’t trust them, but I’m looking into it. So this may be the last time you hear the term LADA from me.

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