June 3, 2003
Daily Care, Diagnosis and Symptoms
Question from an RN in Buffalo, New York, USA:
I am 48 years old, have a family history of type 2 diabetes, was diagnosed with diabetes 14 weeks ago, and I lost 14 pounds in the eight months prior to diagnosis, whereas my weight was stable at 132 pounds for last five years. My doctor did not do any tests to assess what type of diabetes I have and stated that I have type 1 because I am thin, so I was started on bedtime Lantus at the time of diagnosis. At that time my fasting blood sugar was 325 mg/dl [18 mmol/L]; after a month, my hemoglobin A1c was 12.3%.
After months of morning hypoglycemia, my insulin time changed to morning. About four weeks ago, I convinced my doctor to let me try metformin which started at 250 mg twice a day and increased to 500 mg about a week ago. He also added 15 mg of Actos [pioglitazone] four days ago, but my doctor does not feel these medications will help since he feels certain I have type 1. It was only after my insistence that he ordered them.
This concerns me because I think I may very well have type 2. I have two-hour postprandial glucoses ranging 140-225 mg/dl [7.8-12.5 mmol/L], and my fasting levels are usually 110-120 mg/dl [6.1-6.7 mmol/L]. I eat four meals per day with no more than 45 grams of carb per meal. Postprandial elevation times vary although evenings are usually the highest, and my doctor felt that adding Regular insulin in the afternoon would cover this. This is where I am confused.
If I am insulin resistant, I would prefer to address that problem before adding more insulin. I am most concerned with the high postprandial glucoses and also my treatment plan. Is it too early in either type to control elevated postprandial blood sugars? Wouldn’t a C-peptide or GAD test help in confirming a diagnosis of type 1? Isn’t it important to understand the disease process in order to best treat it? I am going crazy trying to manage this!
Answer:
Questions such as the ones you raise are the most common types of questions we see on this site. Points in favor of a diagnosis of type 2 diabetes include your family history and your age. Points in favor of type 1 diabetes are your thin body habitus and your high sugars.
The first thing I try to do is to determine how symptomatic patients are with hyperglycemia. If your sugars are high, even if you have type 2 diabetes, I may treat with insulin in order to decrease the acute symptoms of hyperglycemia. The work-up for type of diabetes can continue with GAD 64 antibody and C-peptide levels.
GAD antibodies are persistently elevated in individuals who have Late-onset Autoimmune Diabetes of Adulthood (LADA). This is a form of type 1 diabetes that is autoimmune in nature, is associated with eventual insulin dependency, but has a variable course in terms of immediate requirement for insulin. If the test is positive, it helps a lot toward identifying you as having a form of type 1 diabetes. The C-peptide levels are important because individuals with type 2 diabetes have levels that are not low, whereas patients with type 1 diabetes have levels that are very low to unmeasurable.
I would suggest that you have these tests. Although I am not sure about your therapy, I would not say it is wrong. Rather, it is important to do these tests to help you and your physician.
JTL
