Table 5.
Relationship of Change in TIR and T > 180 to Change in A1C According to Baseline A1C Level.a
| Overall (N = 455) |
Baseline A1C <7.0% (n =
131) |
Baseline A1C 7.0-7.9% (n =
182) |
Baseline A1C ≥8.0% (n =
142) |
|||||
|---|---|---|---|---|---|---|---|---|
| Estimate | 95% CI for the predicted value | Estimate | 95% CI for the predicted value | Estimate | 95% CI for the predicted value | Estimate | 95% CI for the predicted value | |
| A. Estimation of change in A1C for a given level of CGM metrica | ||||||||
| Estimated Change in A1C from Baseline (%) | ||||||||
| Change in TIR70-180 | ||||||||
| −20% | +0.42 | (−0.76, +1.60) | +0.64 | (−0.35, +1.64) | +0.45 | (−0.55, +1.44) | −0.14 | (−1.14, +0.85) |
| −15% | +0.25 | (−0.92, +1.43) | +0.50 | (−0.49, +1.50) | +0.31 | (−0.69, +1.30) | −0.29 | (−1.28, +0.71) |
| −10% | +0.09 | (−1.08, +1.26) | +0.36 | (−0.63, +1.35) | +0.16 | (−0.83, +1.16) | −0.43 | (−1.42, +0.57) |
| −5% | −0.08 | (−1.25, +1.10) | +0.22 | (−0.77, +1.21) | +0.02 | (−0.97, +1.01) | −0.57 | (−1.56, +0.42) |
| 0% | −0.24 | (v1.41, +0.93) | +0.08 | (−0.91, +1.07) | −0.12 | (−1.11, +0.87) | −0.71 | (−1.70, +0.28) |
| +5% | −0.41 | (−1.58, +0.76) | −0.06 | (−1.06, +0.93) | −0.26 | (−1.25, +0.73) | −0.85 | (−1.84, +0.14) |
| +10% | −0.57 | (−1.74, +0.60) | −0.21 | (−1.20, +0.79) | −0.40 | (−1.39, +0.59) | −0.99 | (−1.99, −0.00) |
| +15% | −0.74 | (−1.91, +0.43) | −0.35 | (−1.34, +0.65) | −0.54 | (−1.54, +0.45) | −1.14 | (−2.13, −0.14) |
| +20% | −0.90 | (−2.08, +0.27) | −0.49 | (−1.49, +0.51) | −0.69 | (−1.68, +0.31) | −1.28 | (−2.27, −0.28) |
| Equation: ΔA1C = |
−0.24 – 0.033×ΔTIR70-180 | 0.08 – 0.028×ΔTIR70-180 | −0.12 – 0.028×ΔTIR70-180 | −0.71 – 0.028×ΔTIR70-180 | ||||
| RMSb | 0.59 | 0.50 | ||||||
| Change in TIR70-140 | ||||||||
| −20% | +0.40 | (−0.79, +1.59) | +0.64 | (−0.37, +1.64) | +0.45 | (−0.55, +1.45) | −0.16 | (−1.17, +0.84) |
| −15% | +0.23 | (−0.95, +1.42) | +0.49 | (−0.51, +1.49) | +0.31 | (−0.69, +1.31) | −0.31 | (−1.31, +0.69) |
| −10% | +0.07 | (−1.12, +1.25) | +0.35 | (−0.65, +1.34) | +0.16 | (−0.84, +1.16) | −0.45 | (−1.45, +0.55) |
| −5% | −0.10 | (−1.28, +1.08) | +0.20 | (−0.80, +1.20) | +0.02 | (−0.98, +1.01) | −0.60 | (−1.60, +0.40) |
| 0% | −0.27 | (−1.45, +0.92) | +0.06 | (−0.94, +1.05) | −0.13 | (−1.12, +0.87) | −0.74 | (−1.74, +0.25) |
| +5% | −0.43 | (−1.62, +0.75) | −0.09 | (−1.09, +0.91) | −0.27 | (−1.27, +0.72) | −0.89 | (−1.89, +0.11) |
| +10% | −0.60 | (−1.78, +0.59) | −0.23 | (−1.23, +0.76) | −0.42 | (−1.42, +0.58) | −1.03 | (−2.03, −0.04) |
| +15% | −0.77 | (−1.95, +0.42) | −0.38 | (−1.38, +0.62) | −0.56 | (−1.56, +0.44) | −1.18 | (−2.18, −0.18) |
| +20% | −0.93 | (−2.12, +0.26) | −0.53 | (−1.53, +0.48) | −0.71 | (−1.71, +0.29) | −1.32 | (−2.33, −0.32) |
| Equation: ΔA1C = |
−0.27 – 0.033×ΔTIR70-140 | 0.06 – 0.029×ΔTIR70-140 | −0.13 – 0.029×ΔTIR70-140 | −0.74 – 0.029×ΔTIR70-140 | ||||
| RMSb | 0.60 | 0.51 | ||||||
| Change in T>180 | ||||||||
| +20% | +0.32 | (−0.86, +1.50) | +0.58 | (−0.40, +1.56) | +0.39 | (−0.59, +1.37) | −0.23 | (−1.21, +0.76) |
| +15% | +0.17 | (−1.00, +1.35) | +0.45 | (−0.53, +1.43) | +0.26 | (−0.72, +1.24) | −0.36 | (−1.34, +0.63) |
| +10% | +0.03 | (−1.15, +1.20) | +0.32 | (−0.66, +1.30) | +0.13 | (−0.85, +1.11) | −0.49 | (−1.47, +0.49) |
| +5% | −0.12 | (−1.30, +1.05) | +0.19 | (−0.79, +1.17) | −0.00 | (−0.98, +0.98) | −0.62 | (−1.60, +0.36) |
| 0% | −0.27 | (−1.44, +0.90) | +0.06 | (−0.92, +1.04) | −0.13 | (−1.11, +0.85) | −0.75 | (−1.73, +0.23) |
| −5% | −0.42 | (−1.59, +0.76) | −0.07 | (−1.06, +0.91) | −0.26 | (−1.24, +0.72) | −0.88 | (−1.86, +0.10) |
| −10% | −0.56 | (−1.74, +0.61) | −0.21 | (−1.19, +0.78) | −0.39 | (−1.38, +0.59) | −1.01 | (−1.99, −0.03) |
| −15% | −0.71 | (−1.89, +0.46) | −0.34 | (−1.32, +0.65) | −0.53 | (−1.51, +0.46) | −1.14 | (−2.12, −0.16) |
| −20% | −0.86 | (−2.04, +0.32) | −0.47 | (−1.45, +0.52) | −0.66 | (−1.64, +0.33) | −1.27 | (−2.26, −0.29) |
| Equation: ΔA1C = |
−0.27 + 0.029×ΔT>180 | 0.06 + 0.026×ΔT>180 | −0.13 + 0.026×ΔT>180 | −0.75 + 0.026×ΔT>180 | ||||
| RMSb | 0.60 | 0.50 | ||||||
| B. Estimation of change in TIR70-180, TIR70-140, and T>180 for a given change in A1C | ||||||||
| Change in A1C | Estimated change in TIR70-180 from baseline (%) | |||||||
| −2.0% | +13.5 | (−3.9, +30.9) | +19.6 | (+3.2, +36.0) | +24.9 | (+9.5, +40.4) | +10.0 | (−10.6, +30.7) |
| −1.5% | +9.9 | (−7.4, +27.2) | +14.7 | (−1.2, +30.7) | +18.5 | (+3.3, +33.6) | +7.1 | (−13.4, +27.7) |
| −1.0% | +6.3 | (−11.0, +23.6) | +9.8 | (−5.8, +25.4) | +12.0 | (−2.9, +26.9) | +4.2 | (−16.2, +24.7) |
| −0.5% | +2.7 | (−14.6, +20.0) | +5.0 | (−10.4, +20.4) | +5.5 | (−9.3, +20.4) | +1.3 | (−19.2, +21.8) |
| 0% | −0.9 | (−18.2, +16.4) | +0.1 | (−15.2, +15.4) | −0.9 | (−15.7, +13.9) | −1.6 | (−22.1, +19.0) |
| +0.5% | −4.5 | (−21.8, +12.8) | −4.8 | (−20.1, +10.5) | −7.4 | (−22.3, +7.5) | −4.5 | (−25.2, +16.2) |
| +1.0% | −8.1 | (−25.5, +9.2) | −9.7 | (−25.2, +5.8) | −13.9 | (−28.9, +1.2) | −7.4 | (−28.2, +13.5) |
| Equation: ΔTIR70-180 = |
−0.92 – 7.21×ΔA1C | 0.09 − 9.75×ΔA1C | −0.93 – 12.93×ΔA1C | −1.56 – 5.80×ΔA1C | ||||
| RMSb | 8.8 | 7.7 | 7.5 | 10.3 | ||||
| Change in A1C | Estimated change in TIR70-140 from baseline (%) | |||||||
| −2.0% | +11.8 | (−5.0, +28.7) | +23.4 | (+6.4, +40.5) | +23.3 | (+7.4, +39.2) | +7.2 | (−10.1, +24.6) |
| −1.5% | +8.5 | (−8.3, +25.3) | +17.5 | (+0.9, +34.0) | +17.2 | (+1.6, +32.8) | +5.0 | (−12.2, +22.3) |
| −1.0% | +5.2 | (−11.6, +21.9) | +11.5 | (−4.7, +27.7) | +11.1 | (−4.4, +26.5) | +2.8 | (−14.4, +20.0) |
| −0.5% | +1.8 | (−14.9, +18.6) | +5.5 | (−10.4, +21.5) | +4.9 | (−10.4, +20.2) | +0.5 | (−16.7, +17.8) |
| 0% | −1.5 | (−18.2, +15.2) | −0.4 | (−16.3, +15.5) | −1.2 | (−16.5, +14.1) | −1.7 | (−19.0, +15.6) |
| +0.5% | −4.8 | (−21.6, +11.9) | −6.4 | (−22.3, +9.5) | −7.3 | (−22.7, +8.0) | −3.9 | (−21.3, +13.4) |
| +1.0% | −8.2 | (−24.9, +8.6) | −12.3 | (−28.4, +3.8) | −13.4 | (−28.9, +2.1) | −6.2 | (−23.7, +11.4) |
| Equation: ΔTIR70-140 = |
−1.50 – 6.66×ΔA1C | −0.42 – 11.9×ΔA1C | −1.19 – 12.2×ΔA1C | −1.70 – 4.47×ΔA1C | ||||
| RMSb | 8.5 | 8.0 | 7.7 | 8.7 | ||||
| Change in A1C | Estimated change in T>180 from baseline (%) | |||||||
| +1.0% | +10.0 | (−9.4, +29.4) | +14.4 | (−0.8, +29.7) | +15.6 | (−1.4, +32.5) | +9.4 | (−14.4, +33.1) |
| +0.5% | +6.0 | (−13.4, +25.3) | +7.4 | (−7.7, +22.5) | +8.6 | (−8.2, +25.3) | +6.3 | (−17.3, +29.8) |
| 0% | +2.0 | (−17.4, +21.3) | +0.3 | (−14.7, +15.4) | +1.5 | (−15.1, +18.2) | +3.1 | (−20.2, +26.5) |
| −0.5% | −2.0 | (−21.4, +17.3) | −6.7 | (−21.9, +8.4) | −5.5 | (−22.2, +11.2) | +0.0 | (−23.3, +23.3) |
| −1.0% | −6.0 | (−25.4, +13.3) | −13.8 | (−29.2, +1.6) | −12.5 | (−29.3, +4.3) | −3.1 | (−26.4, +20.2) |
| −1.5% | −10.0 | (−29.4, +9.4) | −20.8 | (−36.6, −5.1) | −19.5 | (−36.6, −2.4) | −6.2 | (−29.5, +17.2) |
| −2.0% | −14.0 | (−33.5, +5.4) | −27.9 | (−44.1, −11.7) | −26.5 | (−43.9, −9.1) | −9.3 | (−32.8, +14.2) |
| Equation: ΔT>180 = |
1.97 + 8.00×ΔA1C | 0.33 + 14.11×ΔA1C | 1.55 + 14.04×ΔA1C | 3.14 + 6.22×ΔA1C | ||||
| RMSb | 9.8 | 7.6 | 8.4 | 11.7 | ||||
a
Simple linear regression models were used to assess the relationship between change in A1C and change in selected CGM metrics for the entire cohort. For the subgroup analyses by baseline A1C, in part A, slopes were forced to be the same across subgroups since there were no significant interaction between baseline A1C and all 3 predictors; in part B, regression models were done separately in each subgroup since there were significant interactions between baseline A1C and change in A1C.
b
RMS = root mean square error from the least squares regression model.