Optimal Insulin Correction Factor in Post- High Intensity Exercise Hyperglycemia in Adults With Type 1 Diabetes: The FIT Study

FIT is an open-label, repeated measures cross-over study. The overall objective of this study is to investigate the glycemic response of a 0%, 50%, 100% and 150% bolus insulin correction (based on personal insulin correction factor) of post-exercise hyperglycemia in physically active adults with type 1 diabetes (T1D) using multiple daily injections (MDI) in a controlled, but clinically representative, experimental setting. Following a 2 week screening phase, patients will enter an 8 week transition to insulin glargine U300 (Toujeo®) if on another basal insulin, in order to optimize their insulin dose and determine their individual insulin correction factor. The final phase of the study is the intervention phase, which consists of 4 separate visits. At each visit, the patient will perform 15 minutes of high intensity exercise in the morning. If they become hyperglycemic following exercise (blood glucose >8.0 mmol/L), they will receive one of four insulin correction doses (0% 50%, 100%, or 150% of their usual correction factor) in a randomized order. They will be monitored in the clinical pharmacology unit by study staff for the rest of the day and overnight. The patient will wear a continuous glucose monitor (CGM) during each intervention visit. The primary outcome of the study is the greatest net reduction in plasma glucose (YSI) following a 50%, 100% and 150% bolus insulin correction of post-exercise hyperglycemia, compared to no bolus insulin correction. Key secondary outcomes include the mean time spent in post-exercise hyperglycemia (>8.0 mmol/L), post-exercise euglycemia (4.0-8.0 mmol/L) and post-exercise hypoglycaemia (≤ 3.9 mmol/L) within 180 minutes and 24 hours following bolus insulin correction.