Insulin Therapy in Adults with Type 1 Diabetes Mellitus: a Narrative Review

Abstract

Here, we review insulin management options and strategies in nonpregnant adult patients with type 1 diabetes mellitus (T1DM). Most patients with T1DM should follow a regimen of multiple daily injections of basal/bolus insulin, but those not meeting individual glycemic targets or those with frequent or severe hypoglycemia or pronounced dawn phenomenon should consider continuous subcutaneous insulin infusion. The latter treatment modality could also be an alternative based on patient preferences and availability of reimbursement. Continuous glucose monitoring may improve glycemic control irrespective of treatment regimen. A glycemic target of glycated hemoglobin < 7% (53 mmol/mol) is appropriate for most nonpregnant adults. Basal insulin analogues with a reduced peak profile and an extended duration of action with lower intraindividual variability relative to neutral protamine Hagedorn insulin are preferred. The clinical advantages of basal analogues compared with older basal insulins include reduced injection burden, better efficacy, lower risk of hypoglycemic episodes (especially nocturnal), and reduced weight gain. For prandial glycemic control, any rapid-acting prandial analogue (aspart, glulisine, lispro) is preferred over regular human insulin. Faster-acting insulin aspart is a relatively new option with the advantage of better postprandial glucose coverage. Frequent blood glucose measurements along with patient education on insulin dosing based on carbohydrate counting, premeal blood glucose, and anticipated physical activity is paramount, as is education on the management of blood glucose under different circumstances.Plain Language Summary: Plain language summary is available for this article.

Keywords: Continuous subcutaneous insulin infusion; Glycemic control; Insulin analogue; Insulin therapy; Multiple daily injections; Type 1 diabetes mellitus.

Fig. 1

A suggested treatment algorithm for type 1 diabetes mellitus for nonpregnant adults. Asterisk indicates that administration at any time (morning or evening) is appropriate for glargine 300 U/mL (Gla-300) or degludec. The single dagger indicates that evening administration is generally preferred for detemir and glargine 100 U/mL (Gla-100). The double dagger sign indicates a new agent not yet indicated for use with a pump. In some cases, it may be considered as first choice. The section sign indicates possible use as first choice over multiple daily injections (MDI) depending on patient preference if cost, reimbursement, and availability are not an issue after 3–6 months of training with MDI. Can be used as an alternative to MDI if glycemic targets are not met with MDI or if experiencing frequent hypoglycemia. CSII Continuous subcutaneous insulin infusion, NPH neutral protamine Hagedorn