Insulin therapy in type 2 diabetes mellitus TROUBLESHOOTING 2 hypoglycemia

Hypoglycemia — An increased risk of hypoglycemia is a potential complication of insulin therapy. However, patients with type 2 diabetes experience much less frequent hypoglycemia than patients with type 1 diabetes [55].

Although basal insulin is associated with less hypoglycemia than prandial insulin (see 'Insulin initiation' above), hypoglycemia can occur when the dose of basal insulin is titrated to cover meals. If the patient subsequently eats less than usual, hypoglycemia may occur. Alternatively, some patients develop daytime hypoglycemia on a dose of basal insulin that controls fasting blood glucose (FBG). Both of these scenarios lead to obligate snacking, which may fuel insulin-associated weight gain. This problem may be identified by asking about symptoms of hypoglycemia when meals are skipped or snacking to prevent hypoglycemia. Other potential triggers (eg, changes in diet or activity) should be identified. Patients who make significant dietary changes (eg, starting a ketogenic diet) may require substantial reductions in insulin dosing (eg, ≥50 percent reduction).

●Nocturnal hypoglycemia – The dose of basal insulin should be reduced (bedtime dosing if taking twice daily) by 4 units or 10 percent, whichever is greater (algorithm 1). If the patient is taking bedtime NPH, an alternative is to switch to detemir, insulin glargine, or degludec.

Among basal insulin preparations, insulin glargine, detemir, and degludec may have some relatively modest clinical advantages over NPH when pursuing tight glycemic targets (less symptomatic and nocturnal hypoglycemia) with the important disadvantage of high cost. (See 'Choice of basal insulin' above.)

●Daytime hypoglycemia – If the patient is taking prandial insulin, the dose should be decreased at the appropriate meal time(s) by one to three units. The patient should be instructed on how to adjust the prandial dose for meal size and carbohydrate content. In addition, patients should be asked about the timing of their prandial insulin dose and have appropriate timing reinforced if it appears to be contributing to episodes of hypoglycemia (for example, if the patient is taking the insulin following a meal rather than prior to the meal).

If the patient is not taking prandial insulin, the dose of basal insulin should be reduced (by 4 units or 10 percent, whichever is greater) (algorithm 1). If needed (based on self-monitoring of blood glucose), prandial insulin should be added to cover mealtime excursions. If the patient is taking bedtime NPH, an alternative is to switch to insulin glargine or degludec and reduce the total daily basal insulin dose by 10 to 20 percent.

●Severe hypoglycemia – If the patient has a hypoglycemic event requiring the assistance of another person to actively administer carbohydrate (severe hypoglycemia) and there are no apparent changes in diet or activity to account for hypoglycemia, it is prudent to reduce the dose substantially (eg, by 20 to 50 percent) and repeat the titration of the basal insulin.

The management of hypoglycemia in patients with diabetes is reviewed in more detail separately.