Fluctuation of serum basal insulin levels following single and multiple dosing of insulin glargine

Background: The large fluctuations in blood concentrations and activity observed with insulin therapies such as NPH insulin or insulin ultralente may result in hyper- or hypoglycemia. Methods: We compared the fluctuations of these insulins with the long-acting basal insulin analog insulin glargine as a re-analysis of three Phase I studies: (1) glargine with NPH or ultralente [single-dose (0.4 IU/kg), randomized study in healthy volunteers (n = 36)]; (II) glargine or NPH [single-dose (0.3 IU/kg), randomized study in patients with diabetes mellitus Type 1 (DMT1) (n = 20)]; and (III) glargine (tailor-made dose) plus insulin lispro in DMT1 (n = 15 over 11 days). Percent deviation around average serum concentration over 24 h (PF24) was used to determine within-patient fluctuation and mean fluctuation value for each treatment group. Results: Mean PF24 in healthy volunteers (Study 1) was significantly lower with glargine (19.8%) than with NPH and ultralente (31.9% and 47.2%, respectively; both P < 0.001 vs. glargine). Similarly, about half the fluctuation observed with NPH (PF24 25.8%) was seen with glargine (PF24 14.2%; P < 0.001) in DMT1 (Study II). In ambulatory DMT1 patients receiving multiple glargine doses, PF24 values demonstrated that the same low fluctuations (PF24 20%) were retained throughout near-maintenance treatment (Study III). Conclusions: Glargine provided less diurnal fluctuation in serum insulin levels than NPH and ultralente in healthy volunteers and patients with DMT1. This lower fluctuation of glargine over NPH or ultralente can help to reduce hyper- or hypoglycemia risks associated with insulin therapy and accordingly encourage achievement of better blood glucose control.