Interactive diabetes case 4: Uncontrolled diabetes in a 51-year-old patient on insulin and two oral agents – B2

ANSWER — Correct.

The tests for islet cell antibodies return strongly positive. The anti-GAD (glutamic acid decarboxylase) antibody level is 0.645, the anti-IA2 (islet antigen 2) antibody level is 2.132 (reference value is <0.1 for each test). You change the diagnosis to latent autoimmune diabetes in adults (LADA). (See "Interactive diabetes case 4: Uncontrolled diabetes in a 51-year-old patient on insulin and two oral agents – Comment".)

You convert the patient to an intensive insulin regimen, prescribing NPH insulin before breakfast and at bedtime, and lispro insulin before breakfast and supper. The doses are adjusted at each visit in response to the patient's history and glucose diary. You stop glipizide because oral insulin secretagogues (sulfonylureas and glinides) are not indicated in patients who are treated with insulin. After several more visits, the patient is well controlled on the following doses: NPH insulin 12 units before breakfast and 22 units at 10 PM, and lispro insulin 5 to 6 units before breakfast and 6 to 10 units before supper. He adjusts his pre-meal doses based on the pre-meal blood glucose level and the estimated carbohydrate content of the meal. An approach for estimating the dose of short- and very short-acting insulins is described elsewhere. (See "Interactive diabetes case 3: Hypoglycemia in a patient with type 1 diabetes – B2".)

With hindsight, if you had ordered the islet cell antibody tests initially, you would have arrived at the diagnosis sooner. Nevertheless, your approach was reasonable. There was abundant evidence to support the diagnosis of type 2 diabetes in this patient, including his age, obesity, other features of the metabolic syndrome including hypertension and hypercholesterolemia, and a family history. In the interim, you directed your efforts to improving the patient's metabolic control by tailoring his insulin regimen to the glucose values he recorded in his diary and by introducing him to the practice of counting carbohydrates. A further discussion of LADA is located elsewhere. (See "Interactive diabetes case 4: Uncontrolled diabetes in a 51-year-old patient on insulin and two oral agents – Comment".)

To explore the consequences of the other actions, return to the case at the beginning of this sequence. (See "Interactive diabetes case 4: Uncontrolled diabetes in a 51-year-old patient on insulin and two oral agents".)