Interactive diabetes case 16: A 61-year-old patient with uncontrolled type 2 diabetes on two oral agents – A5

ANSWER — Correct.

Insulin is an appropriate treatment for patients with type 2 diabetes who do not reach glycemic goals despite medical nutrition therapy, exercise, and maximum tolerated doses of two oral agents. It is the preferred treatment for such patients when cost is a major consideration [1]. Of the options presented, it is the only therapy likely to reduce glycated hemoglobin (A1C) levels to the goal of <7.0 percent in patients with an A1C >8.5 percent [2].

Properly used, insulin is safe and effective. Most patients with type 2 diabetes will require only one injection a day initially. This may be an injection of NPH insulin or glargine insulin at bedtime or before breakfast or it may be a fixed combination of a basal and a short-acting or rapid-acting insulin before breakfast or supper. The selection and use of insulin formulations in patients with type 2 diabetes is discussed separately. (See "Interactive diabetes case 2: Switching from oral agents to insulin in type 2 diabetes".)

There is no limit to the dose of insulin that may be given. The appropriate dose is the one that reduces the A1C to the target value, usually <7.0 percent, without hypoglycemia. In type 2 diabetes, the dose is usually proportional to the body mass index (BMI). For a patient who has not previously been treated with a basal insulin, or a combination containing a basal insulin, a starting dose of 0.2 units per kilogram of body weight, usually 10 to 20 units, is appropriate. The dose should be increased every five days or so based on blood glucose monitoring until the target values are achieved. The optimal dose, determined by blood glucose monitoring and A1C values, is typically in the range of 0.6 to 1.0 units per kilogram.

In patients treated with insulin, the risk of hypoglycemia is relatively low in patients with type 2 diabetes compared with those who have type 1 diabetes, at least in the first few years of insulin treatment. This risk increases later in the course of type 2 diabetes as absolute endogenous insulin deficiency develops [3]. Weight gain of approximately 2 to 4 kg may occur, typically in those patients who have symptoms of hyperglycemia prior to insulin initiation, are losing glucose and other nutrients in the urine, and are volume depleted. Such patients should be informed about the possibility of weight gain and advised to adhere closely to their diet during the initiation of insulin.

When one of the oral agents is an insulin secretagogue such as a sulfonylurea (as in our patient) or a glinide, it can be discontinued when insulin is started or, preferably, when the glucose values have begun to fall in response to insulin. This will simplify the regimen and reduce costs.

Return to the beginning to explore the other pharmacologic choices offered in this case. (See "Interactive diabetes case 16: A 61-year-old patient with uncontrolled type 2 diabetes on two oral agents".)