Randomized Crossover Comparison of Automated Insulin Delivery vs. Conventional Therapy using an Unlocked Smartphone with Scheduled Pasta and Rice Meal Challenges in the Outpatient Setting.

Background: Automated Insulin Delivery (AID) hybrid closed-loop systems have not been well studied in the context of prescribed meals. We evaluated performance of our interoperable artificial pancreas system (iAPS) in the at-home setting, running on an unlocked smartphone, with scheduled meal challenges in a randomized crossover trial. Methods: Ten adults with type 1 diabetes completed two weeks of AID-based control and two weeks of conventional therapy in random order where they consumed regular pasta or extra-long grain white rice as part of a complete dinner meal on six different occasions in both arms (each meal three times in random order). Surveys assessed satisfaction with AID use. Results: Postprandial differences in conventional therapy were 10,919.0 mg/dL x min (95% CI 3,190.5 to 18,648.0, p=0.009) for glucose area under the curve (AUC) and 40.9 mg/dL (95% CI 4.6 to 77.3, p=0.03) for peak CGM glucose, with rice showing greater increases than pasta. White rice resulted in a lower estimate over pasta by a factor of 0.22 (95% CI 0.08 to 0.63, p=0.004) for AUC under 70 mg/dL. These glycemic differences in both meal types were reduced under AID-based control and were not statistically significant, where 0h-2h insulin delivery decreased by 0.45 units for pasta (p=0.001) and by 0.27 units for white rice (p=0.01). Subjects reported high overall satisfaction with the iAPS. Conclusions: The AID system running on an unlocked smartphone improved postprandial glucose control over conventional therapy in the setting of challenging meals in the outpatient setting.