Simmons D, Hlaing T
Institute of Metabolic Science, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Department of Rural Health, University of Melbourne Shepparton, Vic., Australia.
Diabet Med. 2014 Nov;31(11):1387-92. doi: 10.1111/dme.12518. Epub 2014 Jun 26.
The utility of HbA1c in diabetes diagnosis is reduced in settings associated with altered haemoglobin glycation. We have studied whether HbA1c varies with mean cell volume and mean cell haemoglobin concentration as measures of haemoglobin metabolism.
Randomly selected adults from rural Victoria, Australia, were invited for biomedical assessment. After excluding patients with known diabetes and/or serum creatinine ≥ 0.12 mmol/l, 1315 adults were included. Demography, arthropometric measurements, oral glucose tolerance test, analyses of full blood count and HbA1c were undertaken.
After adjusting for age, sex, ethnicity, BMI, town and socio-economic status, there were no significant differences in haemoglobin, mean cell volume or mean cell haemoglobin concentration by glycaemic status (defined by oral glucose tolerance test). HbA1c was significantly and independently associated with fasting glucose, town, mean cell haemoglobin concentration, ethnicity, age and BMI among men < 50 years (R² = 33.8%); fasting glucose, 2-h glucose, mean cell haemoglobin concentration and town among men ≥ 50 years (R² = 47.9%); fasting glucose, mean cell volume, mean cell haemoglobin concentration, town, 2-h glucose and age among women < 50 years (R² = 46.3%); fasting glucose, mean cell haemoglobin concentration, mean cell volume and 2-h glucose among women ≥ 50 years (R² = 51.6%). A generalized linear model showed a gradient from an adjusted mean HbA1c of 36 (95% CI 34-38) mmol/mol with a mean cell haemoglobin concentration of ≤ 320 g/l to 30 (95% CI 29-31) mmol/mol with a mean cell haemoglobin concentration of > 370 g/l. The gradient across mean cell volume was negative, but only by 1 mmol/mol (0.1%) HbA1c .
A mean HbA1c difference of 5 mmol/mol (0.5%) across the mean cell haemoglobin concentration reference range suggests that an accompanying full blood count examination may be required for its use in the diagnosis of diabetes. Further studies are required to confirm this.
在与血红蛋白糖化改变相关的情况下，糖化血红蛋白（HbA1c）在糖尿病诊断中的效用会降低。我们研究了HbA1c是否会随着作为血红蛋白代谢指标的平均红细胞体积和平均红细胞血红蛋白浓度而变化。
邀请澳大利亚维多利亚州农村地区随机选取的成年人进行生物医学评估。在排除已知糖尿病患者和/或血清肌酐≥0.12 mmol/L的患者后，纳入了1315名成年人。进行了人口统计学、人体测量、口服葡萄糖耐量试验、全血细胞计数分析和HbA1c检测。
在对年龄、性别、种族、体重指数、城镇和社会经济状况进行调整后，不同血糖状态（由口服葡萄糖耐量试验定义）的血红蛋白、平均红细胞体积或平均红细胞血红蛋白浓度无显著差异。在年龄<50岁的男性中，HbA1c与空腹血糖、城镇、平均红细胞血红蛋白浓度、种族、年龄和体重指数显著且独立相关（R² = 33.8%）；在年龄≥50岁的男性中，HbA1c与空腹血糖、2小时血糖、平均红细胞血红蛋白浓度和城镇相关（R² = 47.9%）；在年龄<50岁的女性中，HbA1c与空腹血糖、平均红细胞体积、平均红细胞血红蛋白浓度、城镇、2小时血糖和年龄相关（R² = 46.3%）；在年龄≥50岁的女性中，HbA1c与空腹血糖、平均红细胞血红蛋白浓度、平均红细胞体积和2小时血糖相关（R² = 51.6%）。广义线性模型显示，平均红细胞血红蛋白浓度≤320 g/L时，校正后的平均HbA1c为36（95%可信区间34 - 38）mmol/mol，而平均红细胞血红蛋白浓度>370 g/L时，校正后的平均HbA1c为30（95%可信区间29 - 31）mmol/mol，呈现出梯度变化。平均红细胞体积的梯度为负，但HbA1c仅降低1 mmol/mol（0.1%）。
在平均红细胞血红蛋白浓度参考范围内，HbA1c平均差异为5 mmol/mol（0.5%），这表明在将其用于糖尿病诊断时可能需要同时进行全血细胞计数检查。需要进一步研究来证实这一点。
