Aims/IntroductionTo define a set of criteria using indices of β‐cell function, including results from the glucagon stimulation test, for liraglutide introduction in patients with type 2 diabetes.Materials and MethodsIn the present retrospective cohort study, patients were included in our analysis if their β‐cell function had been evaluated with a glucagon stimulation test and a 24‐h urinary C‐peptide (U‐CPR) excretion test before switching from insulin therapy to liraglutide monotherapy. The efficacy of liraglutide was determined by the extent to which glycemic control was achieved or if glycated hemoglobin levels were maintained at <7.0% after liraglutide monotherapy for 24 weeks.ResultsLiraglutide was effective in 36 of 77 patients. In the liraglutide‐effective cases, the following parameters were higher: fasting C‐peptide (CPR0) levels, C‐peptide levels 6 min after glucagon stimulation (CPR6), the C‐peptide index (CPI; CPR0 × 100/fasting plasma glucose) and stimulated C‐peptide index (S‐CPI; CPR6 × 100/plasma glucose 6 min after glucagon stimulation). U‐CPR did not differ between liraglutide‐effective and liraglutide‐ineffective cases. Using receiver operating characteristic analysis adjusted for baseline characteristics, the independent cut‐off value for effective liraglutide introduction was 0.72 for CPI and 1.92 for S‐CPI.ConclusionsEvaluation of β‐cell function using the glucagon stimulation test is useful for determining the efficacy of liraglutide introduction in patients with type 2 diabetes.

We retrospectively investigated the effect of switching from insulin glargine (IGlar) to insulin degludec (IDeg) on glycemic control in Japanese patients with type 1 diabetes mellitus. We also evaluated the dose of IDeg, and assessed weight gain and the risk of hypoglycemia after switching. Forty-five patients with type 1 diabetes were switched from IGlar (once daily or twice daily) to IDeg (once daily) during routine medical care. Data were collected for 16 weeks after switching from IGlar to IDeg. The mean HbA1c (%) in weeks 4, 8, 12, and 16 was lower than it was in week 0 (8.0 ± 1.0, 8.0 ± 1.4, 7.9 ± 1.1, 7.6 ± 1.0 vs. 8.3 ± 1.3 %, p \ 0.01). The total basal insulin dose (TBD) was significantly lower after 16 weeks of IDeg as compared to IGlar treatment (0.30 ± 0.12 vs. 0.24 ± 0.11 U/kg/day, p = 0.001). In the twice-daily IGlar group, TBD showed a significant decrease from 0.33 ± 0.12 to 0.26 ± 0.11 U/kg/day (p \ 0.001) after switching to IDeg. In the once-daily IGlar group, TBD showed a slight but not significant decrease from 0.23 ± 0.08 to 0.20 ± 0.09 U/kg/day (p = 0.97). Hypoglycemic episodes were transiently increased, but the change was not significant. The blood glucose fluctuation was evaluated from self-monitoring data and the coefficient of variation (CV) was calculated. The CV showed only a minimal change from 48.3 ± 17.1 to 48.6 ± 14.2 % at 12 weeks after switching to IDeg (p = 0.73). In conclusion, once-daily IDeg improved glycemic control in patients with type 1 diabetes compared to the control achieved with IGlar, without increasing the risk of hypoglycemia. When switching from IGlar (especially twice daily), it is recommended that the initial dose of IDeg should be reduced in order to decrease the risk of hypoglycemia.