Safety of a Novel Continuous Glucose Monitoring-Informed Insulin Bolus Calculator Mobile Application for People With Type 1 or Type 2 Diabetes

Abstract

Background: Managing bolus insulin dosing can be a significant burden for people with diabetes, many of whom have limited numeracy skills. Insulin bolus calculators (IBCs) may improve glycemia as well as treatment satisfaction.

Objective: The purpose of this study was to demonstrate the safety of a novel, continuous glucose monitoring (CGM)-informed IBC mobile device app that applies trend arrow adjustments to bolus insulin dose recommendations.

Research design and methods: This clinical trial was an open-label, industry-sponsored single-arm study conducted at two sites. Fifty-four participants with type 1 or type 2 diabetes were enrolled and used the IBC app on their mobile device for 30 days. Study participants were adults who were already using CGM and dosing bolus insulin. The analysis examined both noninferiority and superiority of time in range (TIR) during the study period compared with baseline. Other important end points included hypoglycemia, glucose variability, nocturnal and diurnal TIR, and diabetes distress. The per-protocol (PP) group was defined as participants who used the IBC >30 times during the study.

Results: Mean TIR improved by 3.8% (95% CI 0.7-6.9%) from 69.2 to 73.0% (P = 0.017) in the PP group. This TIR corresponds to a mean of 0.9 more hours per day spent in range, and the improvement was driven by those with type 2 diabetes. There was no increase in measures of hypoglycemia or diabetes distress. Exploratory analysis revealed a reduction in measures of glucose variability. In addition, individuals with type 1 diabetes had greater improvements in diurnal TIR than in nocturnal TIR.

Conclusion: A CGM-informed IBC app that applies trend arrow adjustments to bolus insulin dose recommendations improved TIR without increasing hypoglycemia or diabetes distress in individuals with type 1 or type 2 diabetes.

Figure 1

Sample screenshots of the IBC mobile app. The information icon (lowercase letter i within a circle) at the top right of the glucose value glows red when there is a message to the user that requires action. The user taps the plus icon (plus sign within a circle) to enter data and receive an insulin bolus dose recommendation.