Overview

After launching the t:connect mobile app, the next project goal was to expand the app’s functionality to allow users to initiate a bolus via their phone. A “bolus” is a dose of insulin to correct a high glucose value or to account for eating food, which diabetics need multiple times per day. This type of feature requires a different regulatory review and approval process, since the app is controlling the user's therapy.

Process

My design work on the Mobile Bolus feature was guided by the regulatory strategy, which relied on the existing functionality of the t:slim X2 insulin pump. While the app can make use of mobile screen sizes much larger than the pump, I tried to match pump functionality as much as possible since users would continue to access both their pump and the app.

I created wireframes to determine the right architecture before refining screens and building components to expand on the app’s design system. Collaborating with the Human Factors team, we ran usability tests on different iterations of the designs I would prototype, which we would refine before testing again. Finalizing the app design involved meticulous documentation to prove that the Mobile Bolus app feature had the same functions as the predicate insulin pump the FDA had already approved.

Impact

The Mobile Bolus feature was the first-ever FDA-cleared smartphone application capable of initiating insulin delivery on both iOS and Android. Enabling diabetics to be discrete in how they manage their needs has been extremely well-received by app users. Within the first month after launching the Mobile Bolus feature in 2022, t:connect users had initiated 1 million boluses using the app interface.