Evaluation of Novel Trend Arrow Adjustment Tool for Diabetes Patients Using Continuous Glucose Monitoring to Guide Insulin Bolus Adjustment (TAAT Study)

Continuous glucose monitoring (CGM) provides up to 288 blood glucose levels per day, updated every 5 minutes and displayed in real-time on the insulin pump, which can be used to enhance delivery of insulin through pump therapy. In addition this real-time CGM data includes "trend arrows" which indicate when the blood glucose is rapidly falling or rising thus enabling the pump user to make immediate adjustments in insulin delivery to prevent subsequent low or high blood sugars. The trend arrows are displayed when the blood glucose is rapidly falling or rising. For example, if the glucose is increasing by 1-2 mmol/L over 20 minutes, a single upward arrow alerts the pump wearer, who can then decide to give a bolus of insulin or increase the meal bolus. Should the glucose level be increasing at a rate greater than 2mmol/L over 20 minutes, 2 upward arrows are displayed and the user could decide to give a larger bolus. The purpose of the bolus adjustment is to add insulin for the predicted rise in glucose to prevent or reduce subsequent hyperglycemia. Similarly, a decrease in the insulin bolus is advised if glucose levels are falling as evidenced by one or two downward arrows. However, effective strategies for adjusting insulin boluses based on CGM trend arrows are lacking. The JDRF CGM Study Group recommended that boluses be adjusted based on trend arrows using a standard 10-20% increase/decrease of the total original recommended bolus dose (10% for one arrow up or down, and 20% for two arrows up or down), with the original bolus dose calculated by the pump calculator (i.e. Bolus Wizard). However, the original recommended bolus dose is dependent on the amount of food to be consumed (grams of carbohydrate) and the current blood glucose (if above or below target range), as well as the amount of active insulin, and therefore increasing or decreasing the total recommended bolus by 10-20% may overcompensate for the trend arrows and result in postprandial hypoglycemia. Attempt