Table 1.
Differences in glucose values (mg/dl) from CGM in reference to YSI and SMBG
| No. of paired data points | Absolute difference (mg/dl)*
|
Relative difference (%)†
|
Absolute relative difference (%)*
|
||||
|---|---|---|---|---|---|---|---|
| Mean ± SD | Median | Mean ± SD | Median | Mean ± SD | Median | ||
| YSI in-clinic days 2, 7, and 10§ | 5.0 ± 27.3 | 1.4 | |||||
| Overall | 905 | 25.2 ± 25.4 | 17.3 | 17.9 ± 21.2 | 12.9 | ||
| Day‖ | −0.1 ± 18.3 | −1.2 | |||||
| 2 | 271 | 23.6 ± 21.1 | 16.5 | 4.5 ± 20.5 | 1.7 | 14.4 ± 11.3 | 12.6 |
| 7 | 227 | 21.2 ± 21.0 | 16.0 | 8.7 ± 34.3 | 1.6 | 15.7 ± 14.0 | 11.3 |
| 10 | 407 | 28.4 ± 29.7 | 18.8 | 5.0 ± 27.3 | 1.4 | 21.6 ± 27.9 | 14.5 |
| P | 0.08 | 0.02 | 0.63 | ||||
| SMBG in-clinic days 2, 7, and 10¶ | |||||||
| Overall | 1,130 | −0.9 ± 26.3 | −4.9 | 17.7 ± 19.5 | 13.3 | ||
| Day‖ | 24.8 ± 25.3 | 17.0 | |||||
| 2 | 379 | 23.0 ± 22.5 | 16.0 | 0.2 ± 21.4 | −1.9 | 15.6 ± 14.5 | 12.8 |
| 7 | 317 | 20.9 ± 25.1 | 15.5 | −2.7 ± 21.3 | −6.4 | 15.7 ± 14.6 | 12.5 |
| 10 | 434 | 20.9 ± 25.1 | 15.5 | ||||
| P | 0.03 | 0.002 | 0.002 | ||||
Data are mean ± SD or median unless otherwise indicated.
*
Calculated as absolute value of (sensor − YSI) where, for each paired point, sensor = time-matched continuously measured glucose value and YSI = SMBG values.
†
Calculated as (sensor − YSI)/YSI.
‡Calculated as the absolute value of (sensor − YSI)/YSI.
‖
From the time of sensor insertion (in 24-h increments). P values calculated by the χ2 Kruskal-Wallis test from median values.
§
Percent of points within 20% of reference = 70.8%; percent of points within 30% of reference = 87.6%.
¶
Percent of points within 20% of reference = 73.4%; percent of points within 30% of reference = 88.7%.