Interactive diabetes case 4: Uncontrolled diabetes in a 51-year-old patient on insulin and two oral agents – A4

ANSWER — Incorrect.

The patient's metabolic control deteriorates with increased variability of glucose values at all times of day and an increase in frequency of insulin reactions. Reactions occur most commonly in the afternoon on those days when he takes the largest dose of NPH for morning hyperglycemia. Alarmed and discouraged, he seeks another clinician.

It is rarely, if ever, appropriate to use an intermediate- or long-acting insulin on a sliding scale. It is helpful to think of endogenous insulin secretion as having two components: (1) basal insulin secretion, which inhibits hepatic gluconeogenesis, lipolysis, and ketogenesis; and (2) meal-related pulses, which promote peripheral and hepatic uptake of ingested carbohydrates. The administration of insulin by injection in a patient with autoimmune diabetes should simulate this pattern to the extent possible. Thus, basal insulin doses should not be adjusted on a day-to-day basis but in response to a pattern of glucose values over a period of time. Importantly, the morning dose of an intermediate-acting insulin (eg, NPH) should be adjusted in response to glucose values later in the day, especially between lunch and supper, when it is having its peak effect. (Similarly, the bedtime dose of an intermediate-acting insulin should be adjusted in response to fasting glucose values.) If one wishes to correct for hyperglycemia before lunch, before supper, or at bedtime, one should adjust the dose of the short- or very short-acting insulin given at the previous meal (breakfast, lunch, and supper, respectively). An approach to estimating the dose of short- and very short-acting insulins is reviewed separately. (See "Interactive diabetes case 3: Hypoglycemia in a patient with type 1 diabetes – B2".)

To explore the consequences of the other responses, 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".)