Patient-Reported Outcomes in a Randomized Trial of Closed-Loop Control: The Pivotal International Diabetes Closed-Loop Trial

Abstract

Background: Closed-loop control (CLC) has been shown to improve glucose time in range and other glucose metrics; however, randomized trials >3 months comparing CLC with sensor-augmented pump (SAP) therapy are limited. We recently reported glucose control outcomes from the 6-month international Diabetes Closed-Loop (iDCL) trial; we now report patient-reported outcomes (PROs) in this iDCL trial. Methods: Participants were randomized 2:1 to CLC (N = 112) versus SAP (N = 56) and completed questionnaires, including Hypoglycemia Fear Survey, Diabetes Distress Scale (DDS), Hypoglycemia Awareness, Hypoglycemia Confidence, Hyperglycemia Avoidance, and Positive Expectancies of CLC (INSPIRE) at baseline, 3, and 6 months. CLC participants also completed Diabetes Technology Expectations and Acceptance and System Usability Scale (SUS). Results: The Hypoglycemia Fear Survey Behavior subscale improved significantly after 6 months of CLC compared with SAP. DDS did not differ except for powerless subscale scores, which worsened at 3 months in SAP. Whereas Hypoglycemia Awareness and Hyperglycemia Avoidance did not differ between groups, CLC participants showed a tendency toward improved confidence in managing hypoglycemia. The INSPIRE questionnaire showed favorable scores in the CLC group for teens and parents, with a similar trend for adults. At baseline and 6 months, CLC participants had high positive expectations for the device with Diabetes Technology Acceptance and SUS showing high benefit and low burden scores. Conclusion: CLC improved some PROs compared with SAP. Participants reported high benefit and low burden with CLC. Clinical Trial Identifier: NCT03563313.

Keywords: Adolescents; Adults; Diabetes distress; Hypoglycemia awareness; Hypoglycemia fear; Patient-reported outcomes; Usability.

Conflict of interest statement

Y.C.K. reports receiving supplies from Dexcom, Roche Diabetes, Tandem Diabetes Care, grant support from Medtronic Diabetes, consulting fees from Novo Nordisk, and holding patent US9486172B2 on estimation of insulin sensitivity from CGM and subcutaneous insulin delivery in T1D. L.M.L. reports receiving consulting fees from Dexcom, Sanofi, Eli Lilly, Novo Nordisk, Roche, Boehringer Ingelheim, Johnson & Johnson, INsulet, Insulogic, ConvaTec, and Merck. S.A.B. reports receiving grant support and supplies, paid to her institution from Tandem Diabetes Care, Insulet and Tolerion, and supplies, provided to her institution, from Dexcom and Roche Diagnostics. D.R. has no disclosures. J.E.P. reports receiving grant support, provided to his institution, and consulting fees and speaker fees from Tandem Diabetes Care; grant support, provided to his institution, and advisory board fees from Medtronic; grant support, provided to his institution, and consulting fees from Eli Lilly; grant support and supplies, provided to his institution, from Insulet; and supplies, provided to his institution from Dexcom. L.E. reports receiving consultancy fees from Tandem Diabetes Care and Ypsomed. C.J.L. reports receiving advisory board fees from Sanofi, and grant support, paid to her institution, from Dexcom, Tandem Diabetes Care, Insulet, Abbott Diabetes, Senseonics, and Lexicon Pharmaceuticals. L.H.M. has received speaking/consulting honoraria from Tandem Diabetes and Dexcom, Inc., and also consults for Clinical Sensors and Capillary Biomedical; her institution receives research grants from Medtronic, Tandem Diabetes, Dexcom, Abbott, and Insulet Corp. B.P.K. reports receiving lecture fees and equipment, provided to the University of Virginia, from Dexcom, grant support, paid to the University of Virginia, advisory board fees, and consulting fees from Sanofi, consulting fees and equipment, provided to the University of Virginia, from Tandem Diabetes Care, holding patents 8,562,587 and 9,750,438 B2 on continuous glucose monitor (CGM)—based prevention of hypoglycemia through hypoglycemia risk assessment and smooth reduction of insulin delivery, licensed to Dexcom, for which royalties are received, and holding patent 9,4,30,022 B2 on method and apparatus for modular power management and protection of critical services in ambulatory medical devices, licensed to Dexcom, for which royalties are received. J.W.L. reports receiving consulting fees, paid to his institution, from Animas Corporation, Bigfoot Biomedical, Tandem Diabetes Care, and Eli Lilly. R.W.B. reports receiving consulting fees, paid to his institution, from Insulet, Bigfoot Biomedical, and Eli Lilly, grant support and supplies, provided to his institution, from Tandem and Dexcom, and supplies from Ascenia and Roche. L.G.-F. reports consulting fees from Dexcom, Merck, Abbott Diabetes Care, Johnson & Johnson, and a licensing agreement with the University of Virginia Licensing and Ventures Group to license use of the HFS-II for fees and royalties, part of which fund ongoing research and education efforts related to the problem of hypoglycemia. There were no licensing fees involved in the use of the HFS-II for this study.