Table 2.
Demographic, Clinical, and System Use Characteristics by Time-in-Range During Closed-Loop Control
| Time-in-range 70–180 mg/dL during CLCb |
Univariate, Pc,e | Multivariate, Pd,e | ||||
|---|---|---|---|---|---|---|
| First quartile (n = 25) | Second quartile (n = 25) | Third quartile (n = 25) | Forth quartile (n = 25) | |||
| Baseline glycemic measures | ||||||
| Time-in-range 70–180 mg/dL | 39% ± 11% | 51% ± 12% | 55% ± 11% | 70% ± 14% | <0.001 | <0.001 |
| Baseline demographic and clinical characteristics | ||||||
| Age (years) | 11.4 ± 2.1 | 11.1 ± 2.0 | 10.8 ± 2.1 | 11.7 ± 1.9 | 0.83 | 0.08 |
| Sex: female | 15 (60%) | 11 (44%) | 9 (36%) | 14 (56%) | 0.76 | 0.03 |
| Race/ethnicity: non-Hispanic White | 20 (80%) | 19 (76%) | 22 (88%) | 20 (80%) | 0.75 | 0.48 |
| Weight (kg) | 46 ± 16 | 44 ± 16 | 40 ± 12 | 45 ± 13 | 0.50 | N/A |
| BMI percentile | 63 ± 30 | 63 ± 29 | 62 ± 27 | 60 ± 25 | 0.64 | 0.13 |
| Duration of diabetes (years) | 4.8 ± 2.6 | 6.5 ± 2.7 | 5.2 ± 2.9 | 4.6 ± 3.0 | 0.92 | 0.57 |
| CGM user before baseline | 22 (88%) | 24 (96%) | 23 (92%) | 25 (100%) | 0.02 | 0.13 |
| Insulin pump before baseline | 22 (88%) | 18 (72%) | 23 (92%) | 21 (84%) | 0.93 | 0.69 |
| Detectable C-peptidea | 8 (32%) | 2 (8%) | 7 (28%) | 8 (32%) | 0.37 | 0.06 |
| Highest parent education | 0.14 | 0.06 | ||||
| <Bachelor's degree | 1 (4%) | 3 (12%) | 2 (8%) | 2 (8%) | ||
| Bachelor's degree | 13 (52%) | 13 (52%) | 11 (44%) | 4 (16%) | ||
| ≥Master's degree | 11 (44%) | 9 (36%) | 12 (48%) | 19 (76%) | ||
| Annual household income | 0.10 | 0.21 | ||||
| <$100,000 | 7 (32%) | 10 (40%) | 5 (22%) | 5 (21%) | ||
| $100,000–<$200,000 | 7 (32%) | 7 (28%) | 9 (39%) | 12 (50%) | ||
| ≥$200,000 | 8 (36%) | 8 (32%) | 9 (39%) | 7 (29%) | ||
| CLC system use | ||||||
| CGM use | 96% (93%, 97%) | 98% (96%, 98%) | 96% (93%, 98%) | 98% (97%, 98%) | 0.001 | NA |
| Closed-loop mode use | 92% (88%, 93%) | 94% (91%, 95%) | 94% (91%, 96%) | 94% (92%, 96%) | <0.001 | 0.13 |
| Closed-loop mode use <90% | 9 (36%) | 4 (16%) | 4 (16%) | 0 (0%) | <0.001 | NA |
| CLC system interaction | ||||||
| Total daily insulin per kg | 1.13 ± 0.27 | 0.95 ± 0.27 | 0.88 ± 0.27 | 0.87 ± 0.20 | 0.008 | 0.12 |
| Total daily basal insulin per kg | 0.55 ± 0.15 | 0.47 ± 0.13 | 0.37 ± 0.12 | 0.37 ± 0.11 | <0.001 | NA |
| Average insulin to carb ratio during the daytime (6 am–8 pm) | 10.7 ± 6.3 | 13.7 ± 6.6 | 13.3 ± 5.5 | 11.8 ± 4.1 | 0.99 | NA |
| Average insulin correction factor during the daytime (6 am–8 pm) | 60 ± 42 | 77 ± 48 | 74 ± 41 | 67 ± 33 | 0.83 | NA |
| No. bolus doses per day | 11.8 ± 2.8 | 11.6 ± 2.5 | 11.3 ± 2.6 | 12.0 ± 2.7 | 0.72 | NA |
| No. automatic bolus doses per day | 6.0 ± 1.6 | 4.6 ± 1.7 | 4.0 ± 1.2 | 3.5 ± 1.0 | <0.001 | <0.001 |
| No. user-initiated bolus doses per day | 5.8 ± 2.6 | 6.9 ± 3.1 | 7.3 ± 2.6 | 8.5 ± 2.8 | <0.001 | 0.46 |
| No. user-initiated bolus doses with carb entry per day | 4.2 ± 2.0 | 5.8 ± 3.0 | 6.0 ± 1.7 | 5.8 ± 2.4 | <0.001 | NA |
| No. user-initiated bolus doses with carb entry <3 per day | 6 (24%) | 2 (8%) | 1 (4%) | 2 (8%) | 0.01 | NA |
| Carbohydrate entered per day (g) | 165 ± 67 | 199 ± 81 | 216 ± 70 | 206 ± 84 | 0.009 | NA |
Data are mean ± SD, median (IQR), or n (%).
The detection limit of the assay was 0.003 nmol/L.
Groups based on quartiles are for display only. Analysis was based on time-in-range 70–180 mg/dL as a continuous variable.
Univariate P-values are from linear regression models with continuous time-in-range 70–180 mg/dL at follow-up as the dependent variable and the participant characteristics as the predictor.
Multivariate P-values are from a single linear regression model with continuous time-in-range 70–180 mg/dL at follow-up as the dependent variable and the characteristics as predictors. To avoid multicollinearity, some factors were not included in the multivariate model. These variables are indicated by NA.
P-values have been adjusted to control the false discovery rate.
BMI, body mass index; CGM, continuous glucose monitoring; CLC, closed-loop control.