Objective: To evaluate patient experience and preference of overnight vs. continuous long-term (LT) use of closed-loop control (CLC).

Methods: Ten participants (50% female) with T1D diagnosed for ≥1 year participated in the study, with a mean age of 38.0 years, diabetes duration of 15.7 years, and pre-study HbA1c of 7.5% or 58 mmol/mol. The CLC system is comprised of a CGM and a closed-loop control algorithm embedded on an insulin pump. Participants used the system overnight (ON) for 8 weeks and continuous (24/7) use for another 8 weeks. Semi-structured interviews, based on Technology Acceptance Model, were completed after each condition. As part of the interviews, participants rated difficulty, complexity, trust, and LT use probability on a 5-point Likert scale (1 - not at all, 5 - extremely). They also rated utility of the system in BG management, whether benefits outweigh barriers, and system preference on a nominal scale.

Results: Means for the CLC-ON were Difficulty - 1.1, Complexity - 1.25, Trust - 4.6, and Probability of LT Use - 4.1, while means for CLC-24/7 were Difficulty - 1.1, Complexity - 1.1, Trust - 4.5 and Probability of LT Use - 5.0. There were no differences between conditions with the exception of a trend to prefer long-term use of continuous CLC. All participants reported that CLC-ON and CLC-24/7 made it easier to manage their diabetes and that benefits of using CLC, both overnight and 24/7, outweigh drawbacks. All reported preference for using CLC-24/7 on a LT basis compared to CLC-ON. Only one participant (10%) indicated intention to use different systems based on situation.

Conclusions: Participant-reported experiences with the CLC system were generally consistent for overnight and 24/7 use. The majority did not find the system difficult or complex, found it useful in managing their diabetes, and had high trust in the system. However, for LT adoption, there was a clear preference to use CLC on a continuous basis despite perceived ease of use, utility, and trust in the system overnight.


J. Shepard: None. L. Gonder-Frederick: Employee; Self; HFS-Global. Research Support; Self; Dexcom, Inc., Jaeb Center for Health Research, Tandem Diabetes Care. Speaker's Bureau; Self; Diabetes UK. Stock/Shareholder; Self; BeHealth Solutions. S.A. Brown: Research Support; Self; Ascensia Diabetes Care, Dexcom, Inc., Roche Diabetes Care, Tandem Diabetes Care. L.L. Kollar: None. E. Emory: None. B. Kovatchev: Advisory Panel; Self; Sanofi. Board Member; Self; TypeZero Technologies, Inc. Consultant; Self; Sanofi, Tandem Diabetes Care. Research Support; Self; Dexcom, Inc., Roche Diabetes Care, Tandem Diabetes Care. Speaker's Bureau; Self; Dexcom, Inc. Stock/Shareholder; Self; TypeZero Technologies, Inc. Other Relationship; Self; Johnson & Johnson, Sanofi.


National Institutes of Health

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