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ADA: Efficacy and Safety of Hybrid Closed-Loop Systems in Patients with Type 1 Diabetes

Results from two studies demonstrate improved glycemic control, reduction in nighttime- and exercise-induced hypoglycemia with the use of hybrid closed-loop systems.

Type 1 diabetes can be a complicated disease state to manage. Within the last few years, technological advancement has changed the management of type 1 diabetes. One such advancement is the hybrid closed-loop system, which consist of three important components; an insulin pump to deliver insulin and/or glucagon, a continuous glucose monitor (CGM), and a sophisticated dosing algorithm responding to fluctuating glucose levels. Two recent studies, presented at the ADA 77th Scientific Sessions, investigated the effectiveness of the hybrid closed-loop system in children and adults with type 1 diabetes.

The first study, presented by Bruce Buckingham, MD of Stanford University, focused on evaluating the safety and efficacy of the hybrid closed-loop system in children with type 1 diabetes. Omnipod patch pump, the insulin pump used in this study, is tubeless, waterproof and provides up to 72 hours of nonstop insulin delivery. The pump was paired with the Dexcom G4 CGM sensor and a model predictive control algorithm. Twelve children between the ages of 6 and 12 years old (mean age = 9 years old) with an average diabetes duration of four years were enrolled into the study. These participants were assessed in an inpatient setting for 36 hours with restricted exercise and given meals containing 30-90 grams of carbohydrates.

With the use of Omnipod, participants achieved desired glucose range 69.2% of the time with an average glucose level of 157 mg/dL. Investigators also reported overnight glucose values within desired glucose range 82% of the time with a mean fasting blood glucose level of 136 mg/dL following overnight use. Participants who used the closed-loop system also spent less time in hypoglycemia compared to usual care at home (2% vs. 4%). The results of this study show a variety of benefits for patients using Omnipod. In addition to reducing the stress and worry of a complicated injection regimen, the system also increased the time spent in target plasma glucose levels and reduced the time spent in hypoglycemia.

The second study, presented by Peter Jacobs, PhD of Oregon Health & Science University, assessed whether a hybrid closed-loop system responding automatically to physical exercise would reduce exercise-related hypoglycemia in adults with type 1 diabetes. Twenty adult patients were enrolled in the study and used wearable, wireless heart rate and accelerometer sensors to detect the onset of aerobic exercise. The system, in response to exercise, would deliver an appropriate dose of insulin and/or glucagon to avoid hypoglycemia. Participants underwent four separate 4-day outpatient sessions with four different therapies; dual hormone closed loop system, single hormone closed loop system, predictive low glucose suspend system and usual current standard of care. On days 1 and 4, participants exercised for 45 minutes at 60% VO2max in an inpatient setting and on day 3, participants exercised for 45 minutes with the exercise of their choice in an outpatient setting.

Participants using a dual hormone closed-loop system spent less time in hypoglycemia compared to single hormone closed-loop systems (1.0% vs. 6.3%; p = 0.01), predictive low glucose suspend systems, and current care. Use of the single-hormone closed-loop system also had a lower mean glucose level after exercise compared to dual-hormone closed-loop systems (67 mg/dL vs. 100 mg/dL). Therefore, it can be concluded that using a combination of insulin and glucagon in a closed-loop system, responding automatically to physical exercise, will be the most effective system in reducing exercise-induced hypoglycemia.

The benefits of using a hybrid closed-loop system in both child and adults with type 1 diabetes are clearly outlined in the two studies. Patients and caregivers can be assured these systems are providing better glycemic control during the day and night. Adults with type 1 diabetes can also be assured the use of a dual-hormone system responding automatically to physical exercise can also reduce the risk of exercise induced hypoglycemia. However, these studies are limited due to their short duration of trial. Longer studies in an outpatient setting should be conducted to assess how these systems improve management of diabetes in the long term and how they affect a patient’s quality of life.

Practice Pearls:

  • Hybrid closed-loop systems reduce the burden of managing type 1 diabetes by use of an insulin pump, CGM and dosing algorithm.
  • Hybrid closed-loop systems can improve glycemic control by increasing time spent in target glucose levels during the day and night in patients with type 1 diabetes.
  • Dual-hormone closed-loop systems, responding automatically to physical exercise, can reduce exercise-induced hypoglycemia in adult patients with type 1 diabetes.



American Diabetes Association. Hybrid Closed-Loop System Demonstrates Effectiveness in Controlling Glucose Levels in Children and Adults with Type 1 Diabetes. Press Release. Available at: Accessed June 21, 2017.

Joanna Martinez-Mendez, PharmD Candidate 2018, Lake Erie College of Osteopathic Medicine School of Pharmacy: FL Campus