291-OR: Using the Performance in Exercise and Knowledge (PEAK) Guidelines Incorporated in a Smartphone-Based Decision Support System Improves Glucose Outcomes during Free-Living Exercise

DailyDose is a smart-phone decision support system developed at Oregon Health & Science University that uses Dexcom G6 CGM and Medtonic’s InPen. The app calculates insulin doses using CGM value and trend, insulin-on-board, carbohydrate amount, and exercise information. Insulin dosing and carbohydrate intake recommendations before and after exercise are adjusted according to the 2017 consensus statement by Riddell et al. known as the PEAK Guidelines. Twenty-four adults with T1D, using multiple daily injections of insulin at baseline, completed a two-week run-in period then used the DailyDose intervention for 8 weeks. Participants completed 3 at-home exercise sessions per week, one aerobic exercise video and two other sessions of their choice. We examined the impact of the use of PEAK guidelines on glucose outcomes during exercise comparing 176 exercise sessions done during run-in and 471 sessions done during the intervention period. Glucose outcomes were assessed from start of exercise to 4 hours after the start or until either a meal was consumed, insulin dosed or new exercise session initiated. Mixed effects analysis was used to determine significance of the intervention on glucose outcomes. The nadir of the glucose was lower for the run-in compared with the intervention (120.6 vs. 130.9 mg/dL, P=.012) . Change in glucose from the start of exercise to the nadir was 58.0 for the run-in versus 46.9 for the intervention period (P=.016) . Time in hyperglycemia (>180mg/dL) during the exercise periods trended toward being lower during the intervention (43.8% run-in, 35.0% intervention, P=.059) , as did time in range of 70-180 mg/dL, (54.2% run-in, 62.2% intervention, P=.081) . There was no difference in time in hypoglycemia. Data suggest that use of PEAK within a decision support app can help prevent more severe glucose drops during and after exercise with a trend toward improving time in range.