More broadly, I now wonder if the advent of the new weight loss medications will force the ADA to make its diagnostic algorithm for adult onset type 1 more strict- leaning a tad more toward more false type 2s

We’ll see! 🤷🏻‍♂️

#medsky #diabetes #endo #DM2 #DM1 #obesity

In an ideal world, he would be treated for his obesity regardless of diabetes type, but in the real world, insurances often do not pay for anti-obesity treatment unless the patient has type 2.

So, the likelihood he has type 1 is pretty high, but I don’t feel it’s certain without more information.

On top of that, he has obesity, sleep apnea, diabetes, low t, and high blood pressure- all diseases that would improve with weight loss.

I will admit, being a medical student, I neglected to ask this patient about all of these type 1 risk factors (I plan to).

I do know that his GAD titers were high, though- in the 200s.

Further, evidence of increased risk for type 1 reduce the false positive risk (see left of pic).

This evidence may include young age at diagnosis, family history of autoimmunity, rapid progression to insulin dependence, and lack of obesity/overweight.

These antibodies are also measured in titers and that plays a role in our diagnostic confidence as well. While we break the test into positive and negative categories, this is a continuous number.

Regardless of the category definition, higher titers make us more confident in a type 1 diagnosis.

However, this test can be positive in 2.5% of people without diabetes at all! And a diagnosis based on this test in a population this age with obesity leaves a high risk of a false positive (~60%)

(Picture from Jones et al. 2021)

The guidelines suggest the GAD antibody positivity alone confirms the diagnosis when the doctor is suspicious of type 1 before the test.

So how do we tell who’s who?

For example, bariatric surgery reduced A1c from 8.7% to 7.1% or 1.6% in one study of type 2 (courcoulas et al. 2024). In type 1, this value is substantially less ~0.5% (Kirwan et al. 2016).

I expect weight loss medicines to demonstrate a similar pattern.

The diagnosis of Type 1 vs type 2 diabetes is actually quite important as a diagnosis of type 2 substantially expands our treatment options/ expectations.

Works, not faith

Hannibal green

Or

Hank lecter ?