Based on the following laboratory values received today, what type of diabetes might I have and how might it best be treated? My fasting blood sugar was 180 mg/dl [10.0 mmol/L], A1c 8.4, GAD <1, and C-Peptide 1.0. I am a 37-year-old Caucasian male, 5 feet, 10 inches tall and I weigh 149 pounds. My BMI is 21. My LDL was 79, triglycerides 59, HDL 40, and blood pressure 110/75. My blood sugar does not respond to metformin, no matter what dose is used.

I would be concerned you may have a form of late-onset autoimmune diabetes of adulthood (LADA). In most cases of LADA, there is a positive anti-GAD antibody. However, your thin body habitus, lack of a dyslipidemia profile, and inability to respond to maximum dose metformin suggest insulinopenia, the need for insulin therapy. I take it the C-Peptide was drawn fasting. It is sometimes worthwhile to check the C-Peptide after a meal challenge. The other thought is that when there has been profound hyperglycemia for a long time, the insulin-producing cells don’t make much insulin, even with type 2 diabetes. Using insulin up front and then checking for C-Peptide response to meal challenge may also be helpful.

JTL