Feasibility of Outpatient Fully Integrated Closed-Loop Control

TLDR

The study evaluates the feasibility of a wearable artificial pancreas system, the Diabetes Assistant, using a smartphone as a closed‑loop control platform. Twenty type‑1 diabetes patients underwent 42‑hour trials in outpatient or hybrid settings, using Dexcom Seven Plus/Omnipod CGM and pump linked to DiAs, with an initial 14‑hour open‑loop period followed by 28 hours of closed‑loop control monitored remotely via 3G/WiFi. System communication was maintained 97.7% of the time (807.5 h), surpassing the 80% feasibility threshold and demonstrating that a smartphone can run outpatient closed‑loop control.

Abstract

OBJECTIVE To evaluate the feasibility of a wearable artificial pancreas system, the Diabetes Assistant (DiAs), which uses a smart phone as a closed-loop control platform. RESEARCH DESIGN AND METHODS Twenty patients with type 1 diabetes were enrolled at the Universities of Padova, Montpellier, and Virginia and at Sansum Diabetes Research Institute. Each trial continued for 42 h. The United States studies were conducted entirely in outpatient setting (e.g., hotel or guest house); studies in Italy and France were hybrid hospital–hotel admissions. A continuous glucose monitoring/pump system (Dexcom Seven Plus/Omnipod) was placed on the subject and was connected to DiAs. The patient operated the system via the DiAs user interface in open-loop mode (first 14 h of study), switching to closed-loop for the remaining 28 h. Study personnel monitored remotely via 3G or WiFi connection to DiAs and were available on site for assistance. RESULTS The total duration of proper system communication functioning was 807.5 h (274 h in open-loop and 533.5 h in closed-loop), which represented 97.7% of the total possible time from admission to discharge. This exceeded the predetermined primary end point of 80% system functionality. CONCLUSIONS This study demonstrated that a contemporary smart phone is capable of running outpatient closed-loop control and introduced a prototype system (DiAs) for further investigation. Following this proof of concept, future steps should include equipping insulin pumps and sensors with wireless capabilities, as well as studies focusing on control efficacy and patient-oriented clinical outcomes.