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Figure 1.
Adult-pediatric transfer learning strategy.
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Figure 2.
Predicted vs observed CGM values for patient #242 on the first test day for a 30-min prediction horizon.
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Figure 3.
Predicted vs observed CGM values for patient #242 on the first test day for a 10-min prediction horizon.
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Figure 4.
Predicted vs observed CGM values for patient #242 on the second test day for a 30-min prediction horizon.
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Feature Min Q1 Mean Median Q3 Max Pediatric population
(n = 84)All selected pediatric patients
(n = 84)Time in range (TIR) (%) 31.71 60.04 70.69 72.99 80.45 94.91 Time below range (TBR) (%) 0.00 0.96 2.45 2.21 3.51 10.06 Time above range (TAR) (%) 0.72 17.13 26.86 24.41 39.24 67.62 Coefficient of variation (CV) (%) 22.50 31.07 35.24 34.62 39.24 49.51 Age (years) 12.00 12.75 13.75 14.00 15.00 17.00 Total PA duration (min) 107.97 523.64 844.07 801.78 1,152.65 1,765.00 Years since T1D diagnosis 1.00 7.00 9.05 10.00 12.00 16.00 HbA1c (%) 5.30 6.20 6.98 6.90 7.30 10.50 Weight (kg) 31.75 47.63 57.29 55.11 65.43 99.79 Height (m) 1.37 1.57 1.65 1.65 1.70 1.98 Body Mass Index (kg/m2) 13.67 18.68 20.89 19.83 22.64 32.49 Closed-loop pediatric subgroup
(n = 60)Time in range (TIR) (%) 50.02 63.29 72.09 73.17 79.65 93.42 Time below range (TBR) (%) 0.00 0.86 2.35 2.18 3.34 7.68 Time above range (TAR) (%) 3.96 18.17 25.56 23.37 33.03 47.39 Coefficient of variation (CV) (%) 22.50 30.82 35.15 34.79 39.19 48.71 Age (years) 12.00 13.00 13.95 14.00 15.00 17.00 Total PA duration (min) 107.97 569.66 848.80 808.13 1,179.35 1,765.00 Years since T1D diagnosis 1.00 6.75 8.78 10.00 12.00 15.00 HbA1c (%) 5.30 6.30 6.92 6.90 7.20 10.40 Weight (kg) 31.75 47.97 57.90 55.57 68.04 99.79 Height (m) 1.37 1.59 1.66 1.65 1.73 1.98 Body Mass Index (kg/m2) 13.67 18.68 20.85 19.80 22.40 32.49 Open-loop pediatric subgroup
(n = 23)Time in range (TIR) (%) 31.71 47.27 66.90 65.03 84.50 94.91 Time below range (TBR) (%) 0.21 1.26 2.78 2.42 3.90 10.06 Time above range (TAR) (%) 0.72 9.93 30.32 33.60 49.77 67.62 Coefficient of variation (CV) (%) 22.55 31.96 35.53 34.65 40.10 49.51 Age (years) 12.00 12.00 13.26 13.00 14.00 17.00 Total PA duration (min) 192.90 478.37 843.65 787.97 1,142.50 1,717.50 Years since T1D diagnosis 3.00 9.00 9.96 10.00 11.50 16.00 HbA1c (%) 5.40 6.05 7.11 6.80 8.10 10.50 Weight (kg) 36.29 47.40 55.14 51.71 62.14 83.46 Height (m) 1.40 1.55 1.62 1.63 1.70 1.88 Body Mass Index (kg/m2) 16.60 18.84 20.83 20.36 23.40 26.16 Adult population
(n = 380)Time in range (TIR) (%) 7.55 69.00 74.72 78.01 85.11 99.05 Time below range (TBR) (%) 0.00 1.11 3.11 2.17 4.00 17.41 Time above range (TAR) (%) 0.06 11.04 22.17 19.13 28.49 92.45 Coefficient of variation (CV) (%) 16.53 29.19 33.15 32.90 36.65 50.36 Age (years) 18.00 25.00 36.63 33.00 46.00 70.00 Total PA duration (min) 85.00 726.00 1,220.31 1,026.50 1,430.25 6,329.00 Years since T1D diagnosis 1.00 11.00 18.28 16.00 23.00 66.00 HbA1c (%) 4.80 6.10 6.61 6.50 7.10 9.40 Weight (kg) 46.72 63.50 73.18 70.76 81.19 127.01 Height (m) 1.47 1.63 1.69 1.68 1.75 1.96 Body Mass Index (kg/m2) 18.25 22.80 25.43 24.73 27.16 41.66 TIR: 70–180 mg/dL (3.9–10.0 mmol/L); TBR: < 70 mg/dL (< 3.9 mmol/L); TAR: > 180 mg/dL (> 10.0 mmol/L); CV: 100 × SD/mean glucose. Values summarize participants over their respective observation windows. The closed- and open-loop subgroups exclude one participant who reported using both modes. Bold text is used to distinguish the different cohorts and improve redability. Table 1.
Characteristics of the pediatric and adult populations used for model training.
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Stat RMSE Zone A (%) Zone B (%) Zone C (%) Zone D (%) Hypo D (%) Hyper D (%) Closed-loop subgroup
(n = 60)Prediction horizon: 10 min Min 4.69 95.03 0.00 0.00 0.00 0.00 0.00 Q1 6.44 97.69 0.18 0.00 0.00 0.00 0.00 Median 7.97 99.08 0.72 0.00 0.18 0.18 0.00 Mean 8.51 98.59 1.09 0.00 0.32 0.32 0.00 Q3 10.04 99.64 1.50 0.00 0.49 0.49 0.00 Max 18.65 100.00 4.74 0.00 1.81 1.81 0.21 Prediction horizon: 20 min Min 8.49 83.72 0.00 0.00 0.00 0.00 0.00 Q1 11.65 91.93 2.18 0.00 0.00 0.00 0.00 Median 13.88 94.18 4.37 0.00 0.75 0.75 0.00 Mean 14.33 94.18 4.74 0.00 1.08 1.04 0.04 Q3 16.51 97.74 6.24 0.00 1.84 1.80 0.00 Max 25.32 100.00 14.38 0.00 4.36 4.36 0.93 Prediction horizon: 30 min Min 12.41 70.07 2.50 0.00 0.00 0.00 0.00 Q1 16.43 84.12 6.77 0.00 0.59 0.32 0.00 Median 18.95 87.87 10.07 0.00 1.45 1.45 0.00 Mean 20.09 87.49 10.36 0.02 2.13 1.98 0.14 Q3 23.11 92.53 13.00 0.00 3.00 2.62 0.00 Max 35.66 97.50 25.38 0.43 9.80 9.80 1.52 Open-loop subgroup
(n = 23)Prediction horizon:
10 minMin 3.37 96.50 0.00 0.00 0.00 0.00 0.00 Q1 5.48 99.08 0.00 0.00 0.00 0.00 0.00 Median 6.01 99.00 0.18 0.00 0.00 0.00 0.00 Mean 6.71 99.20 0.55 0.00 0.25 0.25 0.00 Q3 8.35 100.00 0.54 0.00 0.40 0.40 0.00 Max 11.06 100.00 2.55 0.00 1.19 1.19 0.00 Prediction horizon: 20 min Min 7.17 89.18 0.25 0.00 0.00 0.00 0.00 Q1 10.51 93.12 1.76 0.00 0.34 0.34 0.00 Median 12.15 96.01 3.33 0.00 0.98 0.98 0.00 Mean 12.85 95.20 3.69 0.00 1.11 1.09 0.02 Q3 15.41 97.83 4.91 0.00 1.97 1.85 0.00 Max 19.49 99.25 8.64 0.00 3.09 3.09 0.25 Prediction horizon: 30 min Min 10.64 80.05 3.41 0.00 0.00 0.00 0.00 Q1 14.87 85.08 6.15 0.00 0.64 0.64 0.00 Median 18.00 89.78 8.42 0.00 2.31 1.79 0.00 Mean 18.23 88.92 9.05 0.00 2.03 1.95 0.07 Q3 22.51 92.94 11.80 0.00 3.04 3.04 0.00 Max 24.88 96.59 15.78 0.00 6.65 6.65 0.77 RMSE: root mean squared error. Zones A–D and Hypo/Hyper D are Clarke Error Grid (CEG) zone percentages. Hypo D: model predicts target range while patient is in hypoglycemia; Hyper D: model predicts target range while patient is in hyperglycemia. Values summarize the distribution across patients (Min, Q1, Median, Mean, Q3, Max) for each prediction horizon. One patient (# 292) reported using both open- and closed-loop insulin pumps. The participant was excluded from the open- and closed-loop subgroup summary statistics but remained included in the overall analyses. Detailed patient-level results are provided in Supplementary File 2. Bold text is used to distinguish the different cohorts and improve readability. Table 2.
Summary of prediction performance of the adult–pediatric transfer learning strategy for open- and closed-loop insulin pump users at 10-, 20-, and 30-min prediction horizons.
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Patient ID Pump Overall RMSE (mg/dL) (%) Zone Hypo D number RMSE (%) Zone Hyper D number RMSE Prediction horizon: 10 min 150 C 18.65 0.00 0 0.00 0.21 1 118.63 324 C 14.42 0.23 1 30.79 0.00 0 0.00 492 C 14.41 0.21 1 37.79 0.00 0 0.00 44 C 13.39 0.74 4 29.17 0.00 0 0.00 83 C 12.34 0.00 0 0.00 0.00 0 0.00 165 C 11.41 1.03 5 22.21 0.00 0 0.00 535 C 11.25 1.66 8 21.42 0.00 0 0.00 540 O 11.06 0.97 5 19.94 0.00 0 0.00 393 C 10.84 1.30 7 32.96 0.00 0 0.00 254 O 10.83 1.19 5 23.23 0.00 0 0.00 392 C 9.79 1.09 5 32.73 0.00 0 0.00 498 C 9.54 1.81 10 20.80 0.00 0 0.00 242 C 8.42 1.24 7 17.63 0.00 0 0.00 226 C 7.92 1.13 6 20.80 0.00 0 0.00 Prediction horizon: 20 min 150 C 25.32 0.21 1 13.96 0.21 1 132.36 44 C 22.28 1.90 10 26.55 0.19 1 81.91 492 C 21.32 1.90 9 36.44 0.00 0 0.00 389 C 21.08 0.18 1 19.25 0.36 2 75.52 324 C 21.08 1.17 5 26.13 0.93 4 78.83 114 C 20.83 2.61 10 21.90 0.00 0 0.00 404 C 20.21 1.08 6 21.95 0.00 0 0.00 357 C 18.36 4.33 22 23.37 0.00 0 0.00 393 C 17.46 4.36 23 37.55 0.00 0 0.00 290 O 15.39 3.09 12 21.01 0.00 0 0.00 498 C 14.39 3.66 20 27.42 0.00 0 0.00 Prediction horizon: 30 min 150 C 35.66 1.06 2 15.19 0.43 3 118.69 44 C 33.47 3.11 10 35.67 1.17 6 115.04 492 C 31.62 4.12 12 60.08 1.52 7 91.04 114 C 30.67 3.38 17 33.23 0.19 1 112.89 404 C 30.32 2.34 9 25.70 0.72 4 97.26 242 C 26.38 7.69 40 62.20 0.54 3 69.26 357 C 25.90 7.54 38 36.83 0.00 0 0.00 393 C 23.09 6.60 33 40.51 0.19 1 73.19 498 C 23.09 9.80 53 31.89 0.00 0 0.00 290 O 19.64 6.65 25 22.69 0.00 0 0.00 501 C 18.38 7.67 44 27.12 0.00 0 0.00 Pump: O = open-loop insulin pump user, C = closed-loop insulin pump user. RMSE: root mean squared error (mg/dL). Hypo D: model predicts target range while patient is in hypoglycemia; Hyper D: model predicts target range while patient is in hyperglycemia. (%) is the percentage of predictions in that category for the patient; 'Number' is the corresponding count of predictions; the RMSE columns are computed over the predictions within that category (0.00 if none). Bold text is used to distinguish the different cohorts and improve redability. Table 3.
Detailed results for challenging patients at 10-, 20-, and 30-min prediction horizons with the adult–pediatric transfer learning strategy.
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Stat RMSE Zone A (%) Zone B (%) Zone C (%) Hypo D (%) Hyper D (%) Hypo E (%) Hyper E (%) Prediction horizon: 10 min Min 5.83 89.28 0.00 0.00 0.00 0.00 0.00 0.00 Q1 9.71 94.15 0.98 0.00 0.00 0.00 0.00 0.00 Median 11.97 96.68 2.68 0.00 0.00 0.00 0.00 0.00 Mean 12.27 96.13 3.39 0.00 0.48 0.00 0.00 0.00 Q3 14.96 99.02 4.63 0.00 0.76 0.00 0.00 0.00 Max 23.97 100.00 10.54 0.00 3.08 0.00 0.00 0.00 Prediction horizon: 20 min Min 12.03 73.08 3.24 0.00 0.00 0.00 0.00 0.00 Q1 18.69 80.01 9.62 0.00 0.00 0.00 0.00 0.00 Median 23.43 84.94 13.65 0.00 0.00 0.00 0.00 0.00 Mean 23.61 85.05 13.84 0.03 0.92 0.15 0.00 0.00 Q3 28.55 89.58 18.36 0.00 1.14 0.16 0.00 0.00 Max 33.81 96.76 25.24 0.38 5.62 1.27 0.00 0.00 Prediction horizon: 30 min Min 13.27 70.17 3.45 0.00 0.00 0.00 0.00 0.00 Q1 20.98 76.72 10.90 0.00 0.00 0.00 0.00 0.00 Median 27.41 81.54 17.85 0.00 0.09 0.00 0.00 0.00 Mean 27.01 82.35 15.98 0.26 1.06 0.34 0.00 0.01 Q3 33.21 87.73 20.88 0.22 1.84 0.22 0.00 0.00 Max 40.60 96.55 24.68 1.43 5.29 2.96 0.00 0.21 RMSE: root mean squared error. Zones A–C and Hypo/Hyper D and Hypo/Hyper E are Clarke Error Grid (CEG) zone percentages. Hypo D: model predicts target range while patient is in hypoglycemia; Hyper D: model predicts target range while patient is in hyperglycemia; Hypo E: model predicts hyperglycemia while patient is in hypoglycemia; Hyper E: model predicts hypoglycemia while patient is in hyperglycemia. Values summarize the distribution across patients (Min, Q1, Median, Mean, Q3, Max) for each prediction horizon. Bold text is used to distinguish the different cohorts and improve readability. Table 4.
Summary of prediction performance of the adult–pediatric transfer learning strategy for MDI pediatric patients at 10-, 20-, and 30-min prediction horizons.
Figures
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Tables
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