Background and Objective: The safe method of instructing insulin dose reduction in combination with SGLT2 inhibitors, dapagliflozin for patients with type 1 diabetes mellitus has not been clarified. In this study, we conducted a stratified, two-arm, parallel comparative study with the primary endpoint of decreasing the frequency of hypoglycemia by instructing basal insulin dose reduction.

Method: The basal insulin dose to total daily insulin dose (TDD) ratio was defined as less than 40% in group A and more than 40% in group B. Group B was instructed to reduce basal insulin dose, while group A was not.

Results: Twenty-nine patients in group A and 28 patients in group B were included in the analysis due to withdrawal of consent before the start of the study. The frequency of hypoglycemia before and after the intervention was 0.23 times/day in group A to 0.26 times/day and 0.19 times/day in group B to 0.23 times/day, with no significant difference between the two groups (P=0.69). The frequency of ketosis, a secondary endpoint, also increased significantly after the intervention, from 0.013 times/day to 0.086 times/day in Group A (p=0.013) and from 0.013 times/day to 0.059 times/day in Group B (p=0.011). Time In Range on FGM improved from 63.6% to 69.7% in group A and from 59.0% to 69.1% in group B. MAGE improved from 121.7 mg/dL to 105.0 mg/dL in group A and from 123.4 mg/dL to 108.0 mg/dL in group B. DTSQ showed a significant improvement in question 2 regarding hyperglycemia in both groups after the intervention, from 3.6 to 2.5 (p=0.008) in group A and from 3.7 to 2.8 (p=0.017) in group B.

Conclusion: In the patients who were able to self-adjust their insulin dose, there was no significant difference in the number of hypoglycemia occurrences after concomitant use of dapagliflozin with or without instruction to reduce basal insulin dose. Concomitant use of dapagliflozin resulted in less glycemic variability, prolonged TIR and improved patient satisfaction regarding with hyperglycemia.


M. Hamaguchi: Research Support; Spouse/Partner; AstraZeneca K. K. M. Yamazaki: None. T. Tanaka: None. M. Ishii: None. H. Okada: None. K. Mitsuhashi: None. N. Kitagawa: None. G. Hasegawa: None. M. Fukui: None.


AstraZeneca K.K.; Ono Pharmaceutical Co., Ltd.

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