Abstract
AIMS/INTRODUCTION: This study evaluated the effects of the Medtronic MiniMed 770G hybrid closed-loop system on glycemic control and psychological aspects in persons with type 1 diabetes mellitus. MATERIALS AND METHODS: This 3-month prospective observational study included 22 participants with type 1 diabetes mellitus who used the Medtronic MiniMed 640G predictive low-glucose suspend system and were switched to the 770G system. Time in the range of 70-180 mg/dL and glycated hemoglobin levels were evaluated; satisfaction, emotional distress and quality of life were assessed using self-reported questionnaires, including the Diabetes Treatment Satisfaction Questionnaire Status, Problem Area in Diabetes and Diabetes Therapy-Related Quality of Life. RESULTS: Time in the range of 70-180 mg/dL increased (63.5 ± 13.4 to 73.0 ± 10.9% [mean ± standard deviation], P = 0.0010), and time above the range of 181-250 mg/dL decreased (26.9 ± 8.9 to 19.6 ± 7.1%, P < 0.0005). Glycated hemoglobin levels decreased (7.7 ± 1.0 to 7.2 ± 0.8%, P = 0.0021). The percentage of participants with time below the range of 54-69 mg/dL <4% of readings increased from 91% to 100% (P < 0.0005). No significant changes were detected in the satisfaction, emotional distress and quality of life levels, but increased sensor calibration might be related to worsened emotional distress and quality of life. CONCLUSIONS: The hybrid closed-loop system decreased hyperglycemia and minimized hypoglycemia, but did not improve psychological aspects compared with the predictive low-glucose suspend system, probably because sensor calibration was increased.