Low levels of unmodified insulin glargine in plasma of people with type 2 diabetes requiring high doses of basal insulin

Glargine metabolism has been studied in insulin-treated people with type 2 diabetes (T2D) at usual glargine doses of 0.4–0.8 units/kg/day (1,2). In some obese subjects with insulin-resistant T2D, higher basal insulin doses are needed, and the question of safety of glargine (3) is therefore still relevant. Epidemiological studies indicate that the risk of cancer is especially elevated in obese individuals with insulin-resistant diabetes requiring high insulin doses (4). Unmodified insulin glargine has been suggested to confer a higher risk of cancer (3), but prior studies have shown that, at usual doses, an active metabolite (M1) with actions similar to human insulin is the main circulating molecule after glargine injection (1,2). The aim of the current study was to establish the plasma levels of insulin glargine (M0) and its metabolites M1 and M2 (1,2) in subjects with T2D treated long-term with glargine dose $1.2 units/kg/day