Dapagliflozin in patients with type 1 diabetes: A post hoc analysis of the effect of insulin dose adjustments on 24-hour continuously monitored mean glucose and fasting β-hydroxybutyrate levels in a phase IIa pilot study

Diabetes Obes Metab. 2017 Jun;19(6):814-821. doi: 10.1111/dom.12882. Epub 2017 Mar 27.


Aims: To investigate the effects of total daily insulin dose (TDD) reductions on 24-hour continuously monitored mean glucose and fasting β-hydroxybutyrate (a marker for diabetic ketosis/ketoacidosis [DKA]) levels, using patient-level data from a 14-day, pilot study of dapagliflozin in type 1 diabetes (T1DM).

Methods: A post hoc exploratory correlation analysis was performed to determine the relationship between change in TDD and (1) 24-hour mean glucose, assessed by continuous glucose monitoring, and (2) fasting β-hydroxybutyrate, in 70 patients with T1DM receiving insulin and dapagliflozin (1, 2.5, 5 or 10 mg) or placebo. The pharmacodynamic effect of dapagliflozin was estimated as a virtual "insulin dose" using 24-hour urinary glucose excretion values and a recognized insulin-to-carbohydrate counting technique.

Results: Trends for correlations were observed between change in TDD and 24-hour glucose (day 7: r = -0.264, P = .056) and β-hydroxybutyrate (day 7: r = -0.187, P = .133; day 14: r = -0.274, P = .047). The pharmacodynamic effect of dapagliflozin 5 or 10 mg was estimated as equivalent to ~20% of baseline TDD. Higher mean and maximum β-hydroxybutyrate levels were observed on days 7 and 14 in patients with a TDD reduction >20% vs ≤20%.

Conclusions: Over 14 days, decreasing the insulin dose diminished the glucose-lowering effect of dapagliflozin-insulin combination therapy and increased levels of β-hydroxybutyrate. While insulin dose adjustments should always be individualized, these analyses suggest that, as a general rule, TDD reduction in dapagliflozin-treated patients with T1DM should not exceed 20%, to ensure glycaemic control does not deteriorate and to mitigate the potential for an increased risk of DKA.

Keywords: antidiabetic drug; continuous glucose monitoring (CGM); dapagliflozin; glycaemic control; insulin therapy; type 1 diabetes; β-hydroxybutyrate.

Publication types

  • Clinical Trial, Phase II

MeSH terms

  • 3-Hydroxybutyric Acid / blood*
  • Adult
  • Benzhydryl Compounds / administration & dosage*
  • Blood Glucose / analysis
  • Blood Glucose / drug effects
  • Blood Glucose Self-Monitoring / methods
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetes Mellitus, Type 1 / urine
  • Dose-Response Relationship, Drug
  • Drug Therapy, Combination
  • Fasting / blood*
  • Female
  • Glucose / analysis
  • Glucosides / administration & dosage*
  • Humans
  • Hypoglycemic Agents / administration & dosage*
  • Insulin / administration & dosage*
  • Male
  • Middle Aged
  • Pilot Projects


  • Benzhydryl Compounds
  • Blood Glucose
  • Glucosides
  • Hypoglycemic Agents
  • Insulin
  • dapagliflozin
  • Glucose
  • 3-Hydroxybutyric Acid