Department of Endocrinology, Nanshan Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong 518051, People's Republic of China.
J Breath Res. 2018 Jan 9;12(2):026004. doi: 10.1088/1752-7163/aa9081.
In clinical practice, an unexplained discordance between percentage haemoglobin A1c (HbA1c) and the progression of diabetes and its complication is observed. HbA1c is determined by the blood glucose level and the red blood cell (RBC) lifespan. Whether the RBC lifespan changes in diabetic patients remains undefined because of the lack of a convenient and accurate measurement method. In the present study, we aim to observe the RBC lifespan in type 2 diabetic patients with poor blood glucose control by an endogenous carbon monoxide (CO) measurement using a rapid and simplified CO breath test machine. The RBC lifespan, age, RBC count, haemoglobin, haematocrit, fasting blood glucose (FBG) level, HbA1c, blood lipids and the liver and kidney function were compared between 38 diabetic patients and 40 healthy individuals. Compared with the control group, in the diabetic patients, the RBC lifespan was significantly decreased by 17.52 ± 4.58 (86.08 ± 18.13 d versus 103.6 ± 22.02 d, p = 0.00). Although a univariate linear correlation analysis showed that the RBC lifespan was negatively correlated with the FBG level (r = -0.386, p = 0.000), haemoglobin A1c (r = -0.346, p = 0.002) and age (r = -0.291, p = 0.010), a stepwise multiple linear regression analysis showed that the RBC lifespan was most affected by the FBG level (t = -3.554, p = 0.001), but not by HbA1c or age, while HbA1c was most affected by the FBG level (t = 13.989, p = 0.000), but not the RBC lifespan. The RBC lifespan in diabetic patients with poor glycaemic control was reduced. The decrease in the RBC lifespan caused by hyperglycaemia was not associated with HbA1c. Thus, a decrease in the RBC lifespan will lead to an underestimation of the actual level of hyperglycaemia and the progression of disease by HbA1c in type 2 diabetic patients if we do not adjust the RBC lifespan.
在临床实践中，观察到血红蛋白 A1c（HbA1c）百分比与糖尿病及其并发症的进展之间存在无法解释的不一致。HbA1c 由血糖水平和红细胞（RBC）寿命决定。由于缺乏方便和准确的测量方法，糖尿病患者的 RBC 寿命是否发生变化仍未定义。在本研究中，我们旨在通过使用快速简化的 CO 呼气测试机测量内源性一氧化碳（CO）来观察血糖控制不佳的 2 型糖尿病患者的 RBC 寿命。比较了 38 例糖尿病患者和 40 例健康个体的 RBC 寿命、年龄、RBC 计数、血红蛋白、红细胞压积、空腹血糖（FBG）水平、HbA1c、血脂以及肝肾功能。与对照组相比，糖尿病患者的 RBC 寿命显著降低（86.08±18.13 天 vs. 103.6±22.02 天，p=0.00），降幅为 17.52±4.58。虽然单变量线性相关分析显示 RBC 寿命与 FBG 水平呈负相关（r=-0.386，p=0.000），与血红蛋白 A1c 呈负相关（r=-0.346，p=0.002），与年龄呈负相关（r=-0.291，p=0.010），但逐步多元线性回归分析显示 RBC 寿命受 FBG 水平影响最大（t=-3.554，p=0.001），不受 HbA1c 或年龄影响，而 HbA1c 受 FBG 水平影响最大（t=13.989，p=0.000），不受 RBC 寿命影响。血糖控制不佳的糖尿病患者 RBC 寿命缩短。高血糖引起的 RBC 寿命缩短与 HbA1c 无关。因此，如果不调整 RBC 寿命，HbA1c 会低估 2 型糖尿病患者的实际高血糖水平和疾病进展。
