At the time I was diagnosed (two years ago), I was 25 years old, 5 feet 8 inches tall, and I weighed 170 pounds. The first doctor I saw (family practice) said I had type 2 diabetes and gave me Glucophage [metformin], but three months later, the second doctor I saw (an endocrinology resident) said I had type 1 diabetes based upon my age and body size. Since my husband and I were not eager to accept this, we pushed and got a GAD antibody test which was positive.

I started taking 75/25 insulin and stopped the Glucophage, but my control worsened. With approval, I resumed metformin (now generic). I then saw a third doctor who did not question the diagnosis and transitioned me to multiple doses of Humalog with Lantus, and I am still taking metformin. I accepted that I have type 1 diabetes.

I just started seeing a fourth doctor who seems very knowledgeable, and I like him. However, he questioned me intensely about why I was taking metformin, and how it seemed to have a positive effect on my fasting levels. He said people with type 1 sometimes take metformin, but it’s usually much older people who have had diabetes for quite a long time. He implied that he doubted the type 1 diagnosis and asked me to transfer records from the second doctor, which I did. I won’t be seeing him again for three months, but I don’t like the diagnosis being brought into question again. What exactly does he suspect? What other possibilities are there for me? LADA?

I should also note I wasn’t particularly impressed with the competency of the first two doctors I saw. I now weigh 185 pounds, and my current hemoglobin A1c is 6.4%. (13.1% at diagnosis.) I have never had DKA, and never passed out. I addition, type 2 diabetes and obesity runs in family (aunt, grandmother), but one of my mother’s cousins has type 1.

Thanks for a great question. It is a common discussion point. Realize that the common denominator is elevated blood sugars. Type 2 diabetes used to be unlikely before age 40 and was previously restricted to overweight and obese people. In addition, type 1 diabetes used to occur only in people who had a very stormy onset to their diabetes. Now we are identifying people with elevated blood sugars before they are sick and asking the question as to what type of diabetes is present.

Clinical parameters are still important. For instance, obesity, hypertension, elevated lipids, family history, older age, and lack of DKA [diabetic ketoacidosis] are usually seen with type 2 diabetes. However, we have identified that there is this condition we refer to as Latent Autoimmune Diabetes in Adults (LADA) which is a slowly evolving type 1 diabetes that can initially look like type 2 diabetes and respond to oral hypoglycemic agents. The defining test is the elevated titer of insulin antibodies, such as anti-glutamic acid decarboxylase (anti-GAD) antibodies that are elevated with LADA. When these are elevated, it is very likely you have a form of LADA.

It is not clear that insulin therapy in LADA is the absolute form of therapy, although it has been empirically recommended because of the theoretical benefit of resting the pancreas and potentially decreasing its antigenicity. The true test is what happens over time. If you are on insulin, I would stay on it as long as hypoglycemia is not a problem.

Your C-peptide level can be monitored over time. If it is LADA, the usual trend is have a decreased C-peptide level signalling a loss of beta cells function.

These issues are complex. The tools are not foolproof. The proper characterization is difficult, even for diabetes specialists. Your new physician probably wants to look at the data and decide whether the results make sense. It is not a bad idea. I would recommend he get the information. The most important thing is that your blood sugars stay in good order. Keep up the good work. Your results are good now.

JTL