An Unusual Case of Type 1 Diabetes -- or Is It Type 2?

Anne L. Peters, MD, CDE


March 07, 2013

A New Treatment Regimen

I started him at 500 mg daily and watched his blood sugar levels. I had him monitor his blood sugar closely, sending me the results every 3 days. By adding in the metformin, I was able to reduce both his basal and prandial insulin doses by about 30%, so I was feeling good that he was responding to an oral agent. I then added a dipeptidyl peptidase 4 (DPP-4) inhibitor because I wanted to address his mealtime blood sugar levels and hopefully eliminate the prandial insulin because that was what was lowering his blood glucose level. I prescribed the DPP-4 inhibitor and then began to adjust downward his mealtime insulin dose.

In the course of 2 weeks, I was able to stop his premeal insulin, and then over the course of the next few months he was entirely off of basal insulin as well. On a regimen of metformin plus a DPP-4 inhibitor, his A1c level has ranged from 6.4% to 6.6%, which indicates very good control. Furthermore, he no longer has hypoglycemic episodes and he doesn't have to monitor his blood glucose. He occasionally checks his blood sugar level in the morning just to make sure that he is OK, but he no longer needs to test his blood sugar 3-4 times daily before meals.

Even though this patient was on the lean side for patients seen in the United States, Asians can develop type 2 diabetes at a much lower BMI. So, if you see a patient who seems to not quite fit the pattern for either type 1 or type 2 diabetes, measure a fasting insulin level and C-peptide level. If the C-peptide is above 0.8 -1 ng/dL -- it's hard to know what that cut-point should be -- you can surmise that that patient probably has type 2 diabetes rather than type 1. You can manage that patient by sequentially adding back in the oral agents and monitor the patient's response. In the case of my patient, I didn't initially prescribe metformin and a DPP-4 inhibitor simultaneously because I was afraid of causing hypoglycemia. I did it very slowly in a stepwise fashion and was able to get him off of his insulin.

Moreover, I didn't stop his insulin immediately when I determined that he probably had type 2 diabetes. I saw this as a process of getting him from where he was, which was on a multiple daily insulin regimen, to an oral agent regimen -- one that was going to take several months to safely get him to where his diabetes management is much easier and much more successful.

This has been Dr. Anne Peters from Medscape. Thank you.