The study will consist of 4 distinct segments that include routine testing of ketones during usual care, during insulin deficiency, and while taking a SGLT2i in addition to usual care, then with insulin deficiency after the SGLT2i has reached steady state and ingested that morning. We will study 20 adults with T1D who are using Dexcom G6 continuous glucose monitor (CGM), plus any form of insulin delivery. Study participants will be randomized to Group A or Group B. Simultaneous ketone monitoring using a the Biosense® breath ketone analyzer (BKA) and capillary blood beta hydroxybutyrate (BOHB) measurement will be done 2-3 times daily for 2 weeks during each of the outpatient segments. This will generate >800 data points comparing breath acetone, measured in units called ACEs, versus capillary blood BOHB measurements for each 2 week period. On days of insulin withdrawal, which will take place on the Washington University Intensive Research Unit (IRU), frequent monitoring with capillary blood measurements of BOHB (Precision Xtra®, Abbott) will be compared with breath BrAce measurements (Biosense®, Readout) and laboratory measurements of BOHB and acetoacetate. Electrolytes and glucose will also be measured.
This proposed study will test whether measurement of breath acetone (BrAce) can be used for the purpose of identifying ketosis (elevated ketones) in persons with type 1 diabetes (T1D). This is important for the potential use of sodium glucose co-transport inhibitors (SGLT2i) in persons with T1D.