Starting insulin in patients with type 2 diabetes: An individualized approach

Basal-bolus regimens

Basal insulin often does not control postprandial hyperglycemia. The need for multiple doses of insulin (including one or more preprandial doses) is suggested by postprandial glucose values above target (usually > 180 mg/dL) or by a hemoglobin A_1c above goal despite well-controlled fasting glucose levels. This usually becomes evident when the total daily dose of basal insulin exceeds 0.5 units/kg. Patients newly diagnosed with diabetes who have a hemoglobin A_1c higher than 10% may also respond better to an initial basal-bolus regimen.

Available bolus insulins include lispro, aspart, glulisine, regular insulin, and the newly approved Technosphere inhaled regular insulin (Table 4).^12–14 They can be taken before each meal, and the total bolus dose usually represents 50% of the total daily dose.²² Rapid-acting insulins have faster onset, shorter duration of action, and more predictable pharmacokinetics, which makes them preferable to regular insulin (Figure 1).¹⁵ Inhaled insulin is another option, but it is contraindicated in patients with chronic obstructive pulmonary disease or asthma because of the increased risk of acute bronchospasm.¹²

Alternatively, the transition to a basal-bolus regimen can be accomplished with a single dose of bolus insulin before the main meal, using a dose that represents approximately 10% of the total daily dose. Additional bolus doses can be added later based on the glycemic control. The adjustment of the preprandial insulin dose is done once or twice weekly, based on the postprandial glucose levels.¹⁰

Premixed combinations of long- and short-acting insulins in ratios of 50% to 50%, 70% to 30%, or 75% to 25% can be considered in patients who cannot adhere to a complex insulin regimen. A propensity-matched comparison of different insulin regimens (basal, premixed, mealtime plus basal, and mealtime) in patients with type 2 diabetes revealed that the hemoglobin A_1c reduction was similar between the different groups.²³ However, the number of hypoglycemic episodes was higher in the premixed insulin group, and the weight gain was less in the basal insulin group.

While premixed insulins require fewer injections, they do not provide dosing flexibility. In other words, dose adjustments for premixed insulins lead to increases in both basal and bolus amounts even though a dose adjustment is needed for only one insulin type. Thus, this is a common reason for increased hypoglycemic episodes.

Continuous subcutaneous insulin infusion

Patients who are engaged in their care are more likely to succeed in their treatment

A meta-analysis showed that continuous subcutaneous insulin infusion (ie, use of an insulin pump) was similar to intensive therapy with multiple daily insulin injections in terms of glycemic control and hypoglycemia.²⁴ Since both options can lead to similar glucose control, additional factors to consider when initiating insulin infusion include lifestyle and technical expertise. Some patients may or may not prefer having a pump attached for nearly all daily activities. Additionally, this type of therapy is complex and requires significant training to ensure efficacy and safety.²⁵

WHAT IS THE COST OF INSULIN THERAPY?

A final factor to keep in mind when initiating insulin is cost (Table 4).^12–14 Asking patients to check their prescription insurance formulary is important to ensure that an affordable option is selected. If patients do not have prescription insurance, medication assistance programs could be an option. However, if a patient is considering an insulin pump, insurance coverage is essential. Depending on the manufacturer, insulin pumps cost about $6,000 to $7,000, and the additional monthly supplies for the pump are also expensive.

If patients are engaged when considering and selecting insulin therapy, the likelihood of treatment success is greater.^26–28