Wentholt Iris M, Vollebregt Marit A, Hart Augustus A, Hoekstra Joost B, DeVries J Hans
Department of Internal Medicine, Academic Medical Center, PO Box 22660, 1100 AD Amsterdam, Netherlands.
Diabetes Care. 2005 Dec;28(12):2871-6. doi: 10.2337/diacare.28.12.2871.
We examined the reliability of two continuous glucose sensors in type 1 diabetic patients at night and during rapid glucose excursions and verified the hypothesized nocturnal hypoglycemic drift of the needle-type sensor (CGMSgold) and delay of the microdialysis sensor (GlucoDay).
Blood was sampled overnight twice per hour in 13 patients. Rapid-acting insulin was given subcutaneously 30 min after breakfast. Sampling once per minute started 45 min after breakfast and 75 min after insulin injection for 30 min, with the aim of determining peak and nadir glucose values. Mean absolute differences (MADs) between sensor and blood glucose values were calculated. Sensor curves were modeled for all patients using linear regression. Horizontal and vertical shifts of sensor curves from the blood glucose curves were assessed. A vertical shift indicates sensor drift and a horizontal shift sensor delay.
Drift was minimal in the needle-type and microdialysis sensors (-0.02 and -0.04 mmol/l). Mean +/- SD delay was 7.1 +/- 5.5 min for the microdialysis sensor (P < 0.001). MAD was 15.0% for the needle-type sensor and 13.6% for the microdialysis sensor (P = 0.013). After correction for the 7-min delay, the microdialysis MAD improved to 11.7% (P < 0.0001).
The microdialysis sensor was more accurate than the needle-type sensor, with or without correction for a 7-min delay. In contrast to the previous version, the current needle-type sensor did not exhibit nocturnal hypoglycemic drift. Continuous subcutaneous glucose sensors are valuable adjunctive tools for glucose trend analyses. However, considering the large MADs, individual sensor values should be interpreted with caution.
我们研究了两种连续血糖传感器在1型糖尿病患者夜间和血糖快速波动期间的可靠性，并验证了针型传感器（CGMSgold）夜间低血糖漂移的假设以及微透析传感器（GlucoDay）的延迟情况。
对13例患者每小时进行两次夜间采血。早餐后30分钟皮下注射速效胰岛素。早餐后45分钟且胰岛素注射后75分钟开始每分钟采样一次，持续30分钟，目的是确定血糖峰值和谷值。计算传感器与血糖值之间的平均绝对差值（MAD）。使用线性回归对所有患者的传感器曲线进行建模。评估传感器曲线相对于血糖曲线的水平和垂直偏移。垂直偏移表示传感器漂移，水平偏移表示传感器延迟。
针型和微透析传感器的漂移极小（分别为-0.02和-0.04 mmol/L）。微透析传感器的平均±标准差延迟为7.1±5.5分钟（P<0.001）。针型传感器的MAD为15.0%，微透析传感器为13.6%（P = 0.013）。校正7分钟延迟后，微透析传感器的MAD提高到11.7%（P<0.0001）。
无论是否校正7分钟延迟，微透析传感器都比针型传感器更准确。与之前的版本相比，当前的针型传感器未表现出夜间低血糖漂移。连续皮下血糖传感器是用于血糖趋势分析的有价值的辅助工具。然而，考虑到较大的MAD，应谨慎解读单个传感器值。
