Figures (1)  Tables (4)

    • Figure 1. 

      Proportion of time spent in the different glycemic ranges during the FCL treatment period and the control period. The percentages displayed are the calculated median value per category. As a result, percentages may not total to 100% as a result of skewed distributions and rounding.

    • Characteristic Participants (n = 15)
      Age (years) 14.1 ± 1.5
      Gender
      Male 10 (66.7%)
      Female 5 (33.3%)
      BMI (kg/m2) 20.1 ± 2.8
      HbA1c (%; mmol/mol) 7.1 ± 1.5; 58.3 ± 7.1
      Current treatment
      HCL 11 (73.3%)
      CSII 2 (13.3%)
      MDI 2 (13.3%)
      Current sensor
      Guardian 4 9 (60.0%)
      Dexcom G6 4 (26.7%)
      FreeStyle Libre 2 2 (13.4%)
      BMI, body mass index; HCL, hybrid closed-loop; CSII, continuous subcutaneous insulin infusion; MDI, multiple daily injections.

      Table 1. 

      Baseline characteristics

    • Outcome measureFCL treatment periodControl periodp-value
      Time in range (TIR; 3.9−10 mmol/L)74.9% (73.1%−81.0%)61.3% (53.7%−68.2%)< 0.001
      Daytime*68.1% (65.1%−75.0%)57.7% (52.3%−64.9%)0.002
      Nighttime**95.0% (93.0%−96.2%)74.7% (61.4%−82.5%)< 0.001
      Time in tight range (TITR; 3.9−7.8 mmol/L)54.3% (50.7%−58.7%)39.8% (33.4%−45.1%)0.001
      Daytime44.9% (42.4%−49.8%)36.7% (31.6%−42.2%)0.012
      Nighttime79.0% (74.6%−81.5%)52.8% (42.0%−56.2%)< 0.001
      Time below range (TBR; < 3.9 mmol/L)0.8% (0.4%−1.7%)2.1% (0.9%−3.3%)0.022
      Daytime0.9% (0.4%−2.0%)2.2% (1.1%−4.0%)0.015
      Nighttime0.5% (0.1%−0.9%)1.2% (0.0%−1.8%)0.208
      Time below range (TBR; < 3.9 mmol/L)0.8% (0.4%−1.7%)2.1% (0.9%−3.3%)0.022
      Daytime0.9% (0.4%−2.0%)2.2% (1.1%−4.0%)0.015
      Nighttime0.5% (0.1%−0.9%)1.2% (0.0%−1.8%)0.303
      Time below range level 2 (TBR2; < 3.0 mmol/L)0.0% (0.0%−0.2%)0.3% (0.1%−1.0%)0.048
      Daytime0.1% (0.0%−0.2%)0.3% (0.1%−0.9%)0.048
      Nighttime0.0% (0.0%−0.0%)0.2% (0.0%−0.4%)0.139
      Time above range (TAR; > 10.0 mmol/L)24.5% (17.5%−25.9%)36.2% (26.8%−45.0%)0.001
      Daytime31.3% (23.3%−33.3%)41.4% (32.6%−45.1%)0.004
      Nighttime4.3% (2.9%−5.5%)24.0% (13.1%−37.2%)< 0.001
      Time above range Level 1 (TAR1; 10.0−13.9 mmol/L)16.7% (15.1%−19.7%)22.8% (21.8%−27.2%)0.001
      Daytime21.8% (19.7%−25.5%)24.7% (22.8%−29.0%)0.035
      Nighttime3.5% (2.5%−5.0%)17.1% (11.5%−21.0%)< 0.001
      Time above range Level 2 (TAR2; > 13.9 mmol/L)4.7% (3.1%−7.8%)10.5% (7.0%−15.9%)0.001
      Daytime6.1% (4.2%−10.2%)13.1% (9.1%−17.3%)0.001
      Nighttime0.0% (0.0%−1.1%)2.7% (1.6%−8.6%)0.001
      Median blood glucose concentration (mmol/L)7.4 (7.2%−7.7%)8.5 (8.0%−9.6%)0.001
      Daytime8.1 (7.6%−8.3%)9.2 (8.3%−9.4%)0.004
      Nighttime6.5 (6.4%−6.7%)7.7 (7.5%−8.4%)< 0.001
      Glycemic variability
      Standard deviation (SD; mmol/L)2.9 (2.7%−3.2%)3.2 (3.1%−4.0%)0.001
      Coefficient of variation (CV)35.7% (32.9%−39.0%)38.8% (34.5%−41.6%)0.121
      Interquartile range (IQR; mmol/L)3.7 (3.2%−3.9%)4.8 (4.3%−5.5%)< 0.001
      Daily insulin use (units)57.3 (52.6%−68.7%)46.6 (37.4%−55.3%)< 0.001
      Daily glucagon use (mg)0.55 (0.37%−0.65%)−
      * Daytime was defined as 06:00−24:00, ** Nighttime was defined as 24:00−06:00. Data are expressed as the median (IQR). TIR was the primary endpoint, tested at a significance threshold of α = 0.05. TITR, TBR, TAR, and median glucose were the key secondary endpoints, evaluated using a Bonferroni-adjusted significance threshold of α = 0.0125. All other metrics were considered exploratory and are reported with nominal p-values. Statistically significant results after correction for multiple comparisons are indicated in bold. n = 15.

      Table 2. 

      Outcome measures of the FCL treatment period and the control period.

    • Questionnaire FCL treatment period Control period p-value
      DTSQs: Parents 40.5 (38.0–45.0) 35.0 (28.5–39.0) 0.083
      Perceived diabetes control 9.0 (6.3–10.0) 5.0 (3.5–6.0) 0.028
      Perceived hypoglycemia 2.0 (1.3–2.8) 3.0 (2.0–4.0) 0.028
      Perceived hyperglycemia 2.0 (1.3–4.8) 5.0 (4.0–5.0) 0.047
      DTSQs: Adolescents 38.0 (35.0–44.0) 35.0 (27.0–39.0) 0.042
      Perceived diabetes control 9.0 (6.0–10.0) 5.0 (4.0–8.0) 0.077
      Perceived hypoglycemia 1.0 (1.0–2.0) 3.0 (2.0–3.0) 0.027
      Perceived hyperglycemia 2.0 (1.0–4.0) 4.0 (3.0–5.0) 0.054
      INSPIRE: Parents 81.0 (69.0–87.0) 72.0 (65.5–6.5) 0.157
      INSPIRE: Adolescents 73.0 (69.0–75.0) 75.0 (66.0–82.0) 0.339
      TAS: Parents 21.5 (20.0–23.0) 19.0 (17.0–21.0) 0.005
      TAS: Adolescents 22.0 (19.0–23.0) 20.0 (19.0–21.0) 0.893
      DTSQs, Diabetes Treatment Satisfaction Questionnaire status; INSPIRE, Insulin Delivery Systems: Perceptions, Ideas, Reflections and Expectations; TAS, Technology Acceptance Scale. Data are expressed as the median (IQR). Sample sizes: Parents (n = 11); adolescents (n = 13).

      Table 3. 

      Person-reported outcome measures assessing treatment expectations, trust, and satisfaction.

    • Adverse events, categorized FCL training period FCL treatment period
      Side effects of sensors
      Skin reactions, infections or damage 5 2
      Side effects of insulin infusion set
      Skin reactions, infections or damage 4 −
      Side effects of glucagon
      Skin reactions, infections or damage at infusion site 7 −
      Nausea 4 −
      Vomiting 1 −
      Abdominal pain 2 −
      Headache 3 1
      Side effects of FCL treatment
      (Sensation of) hypoglycemia 1 −
      General malaise 1 −

      Table 4. 

      Overview of all reported adverse events