Table 1.
Glycemic Outcomes
| Standard bolus delivered with meal | Standard bolus delivered before meal | Over-bolus delivered with meal | No bolus delivered with meal | |
|---|---|---|---|---|
| Number of participants | 42 | 40 | 40 | 46 |
| Number of breakfasts | 51 | 40 | 40 | 46 |
| Meal and insulin delivery characteristics | ||||
| Meal size (g of CHO) | 68 (60, 78) | 67 (58, 75) | 63 (51, 75) | 50 (50, 50) |
| Normalized meal size (g of CHO/kg of body weight) | 1.00 (0.99, 1.00) | 1.00 (0.98, 1.00) | 0.99 (0.95, 1.00) | 0.74 (0.64, 0.93) |
| Minutes from bolus to start of meal | 0 (−2, +1) | −15 (−16, −14) | +1 (−1, +1) | — |
| Meal bolus size (U) | 6.0 (5.2, 8.8) | 6.0 (4.8, 9.5) | 7.4 (6.0, 10.4) | — |
| Normalized meal bolus size (unitless)a | 0.96 (0.94, 0.97) | 0.96 (0.95, 0.97) | 1.24 (1.22, 1.26) | — |
| Cumulative basal insulin delivery at 4 h (% of open-loop basal) | 103% (77%, 154%) | 118% (72%, 147%) | 80% (53%, 110%) | 204% (173%, 251%) |
| Cumulative basal plus bolus insulin delivery at 4 h (U)b | 10.4 (7.8, 13.3) | 11.5 (9.7, 13.8) | 11.9 (9.3, 14.6) | 8.8 (7.3, 11.1) |
| Glycemic outcomes | ||||
| Metrics at start of meal | ||||
| Baseline glucosec | 124 (98, 174) | 148 (124, 180) | 125 (111, 142) | 125 (115, 144) |
| Metrics over 4 h | ||||
| Number of YSI measurements | 11 (11, 11) | 11 (11, 11) | 11 (11, 11) | 11 (11, 11) |
| % of meals with a YSI value | ||||
| ≤60 mg/dL | 0 | 1 (3%) | 2 (5%) | 0 |
| ≤70 mg/dL | 2 (4%) | 3 (8%) | 2 (5%) | 0 |
| >180 mg/dL | 43 (84%) | 35 (88%) | 31 (78%) | 44 (96%) |
| >250 mg/dL | 28 (55%) | 20 (50%) | 10 (25%) | 37 (80%) |
| >300 mg/dL | 15 (29%) | 12 (30%) | 5 (13%) | 19 (41%) |
| >400 mg/dL | 1 (2%) | 0 | 2 (5%) | 0 |
| % of YSI values | ||||
| ≤70 mg/dL | 0% (0%, 0%) | 0% (0%, 0%) | 0% (0%, 0%) | 0% (0%, 0%) |
| 71–180 mg/dL | 27% (9%, 64%) | 27% (10%, 55%) | 55% (30%, 85%) | 18% (9%, 27%) |
| >180 mg/dL | 73% (36%, 91%) | 73% (43%, 90%) | 41% (9%, 70%) | 82% (73%, 91%) |
| Mean glucose (mg/dL) | 204 (159, 249) | 203 (164, 250) | 168 (150, 205) | 231 (208, 245) |
| Glucose CV | 22% (15%, 25%) | 21% (16%, 25%) | 18% (15%, 26%) | 21% (17%, 25%) |
| Nadir (mg/dL) | 124 (98, 167) | 133 (97, 176) | 114 (101, 138) | 139 (121, 151) |
| Peak (mg/dL) | 261 (206, 319) | 250 (217, 307) | 220 (182, 249) | 287 (263, 313) |
| Excursion (peak minus baseline)c | 121 (70, 171) | 105 (60, 130) | 102 (67, 134) | 156 (123, 180) |
| Area under the curve 180 (mg/dL/min)d | 34 (6, 69) | 29 (9, 72) | 13 (0, 29) | 56 (37, 70) |
| % meals with a Hypoglycemia red light | 9 (18%) | 5 (13%) | 8 (20%) | 3 (7%) |
| Hypoglycemic treatment interventionse | 0 | 1 (3%) | 1 (3%) | 0 |
| Hyperglycemic treatment interventionse | 1 (2%) | 0 | 2 (5%) | 0 |
| Metrics at 4 h | ||||
| Glucose at 4 h | 175 (134, 213) | 174 (138, 205) | 143 (109, 174) | 201 (161, 226) |
| % of meals with a YSI value at 4 h | ||||
| ≤60 mg/dL | 0 | 0 | 1 (3%) | 0 |
| ≤70 mg/dL | 0 | 0 | 1 (3%) | 0 |
| 71–180 mg/dL | 27 (53%) | 22 (55%) | 31 (78%) | 16 (35%) |
| >180 mg/dL | 24 (47%) | 18 (45%) | 8 (20%) | 30 (65%) |
| >250 mg/dL | 5 (10%) | 4 (10%) | 2 (5%) | 5 (11%) |
| >300 mg/dL | 2 (4%) | 0 | 2 (5%) | 1 (2%) |
| >400 mg/dL | 0 | 0 | 0 | 0 |
Data are median (25th, 75th percentiles) values or n (%) as indicated.
a
BolusNORM=(bolusACTUAL×carbohydrate ratio)/meal size.
b
Includes the meal boluses, correction boluses, and insulin delivered by the controller.
c
Eleven baseline YSI values and excursions were missing (three with standard bolus delivered with meal, two with standard bolus delivered before meal, three with over-bolus delivered with meal, and three with no bolus delivered with meal).
d
Area under the curve calculated for each meal and divided by the time.
e
Hypoglycemic treatments preceded by a red light were not counted as an intervention, and YSI values were not imputed.
CHO, carbohydrate; CV, coefficient of variation.