High hemoglobin glycation index is associated with increased risk of diabetes: A population-based cohort study in China.

Purpose: The hemoglobin glycation index (HGI) quantifies the mismatch between glycated hemoglobin A1c and average glycemia among individuals. Currently, it is unknown the potential role of HGI in exhaustively evaluating the progression of glucose metabolism/the risk of developing diabetes mellitus. Therefore, this study aimed to investigate the association between HGI and the risk of incident diabetes. Methods: A total of 7,345 participants aged at least 40 years and without diabetes were divided into three groups according to the tertile of their baseline HGI level and followed for a median of 3.24 years to track new-onset diabetes. Using multivariate Cox regression analyses, we explored the association between the HGI, both categorized and continuous, and incident diabetes. Results: During follow-up, 742 subjects (263 males and 479 females) developed diabetes mellitus. Higher HGI was associated with an increased risk of diabetes, even when adjusted for confounding factors, and every standard deviation increase in HGI was associated with a significant risk increase of 30.6% for diabetes (hazard ratio 1.306, 95% confidence interval 1.232-1.384). Conclusions: Participants with a higher HGI were at a higher risk of future diabetes, irrespective of their glycemic conditions. Consequently, HGI may be employed to identify individuals at high risk for diabetes.

Study of a newly developed high-performance liquid chromatography analyser for glycosylated haemoglobin measurements in blood containing haemoglobin variants in the Japanese population.

BACKGROUND: This study examined the new high-performance liquid chromatography analyser HLC-723GX (GX) and investigated its ability to both measure glycosylated haemoglobin (HbA1c) values and determine whether haemoglobin variants could cause interference with these measurements in the Japanese population. METHODS: For the basic GX examination, the within- and between-run precision, linearity of measurements, correlation of HbA1c values with current systems and the interference of chemically modified haemoglobin were determined. GX interference caused by the haemoglobin variant was examined by analysing 39 clinical laboratory samples that contained haemoglobin variants. RESULTS: Good within- and between-run precision were found, with the coefficients of variation at ≤1.0%. A wide range of HbA1c measurement values were confirmed, with the HbA1c values strongly correlated with the results of the currently used HLC-723G8 system. Chemically modified haemoglobins were prepared by adding glucose, sodium cyanate, acetaldehyde or acetylsalicylic acid to normal blood samples. None of these samples had any influence on the HbA1c values determined by GX. GX analysis showed haemoglobin variants that eluted after HbA0 and were similar to HbD, or HbS had HbA1c values that were close to those measured by boronate affinity chromatography and immunoassay. GX found lower HbA1c values in blood that contained HbE or haemoglobin variants, which elute before or at nearly the same time as HbA0. CONCLUSIONS: GX is useful for the analysis of HbA1c samples that contain HbD, HbS, HbC and haemoglobin variants, even though the elution times are similar. However, a countermeasure is needed in order to avoid overlooking other haemoglobin variants in Japan.

Agar gel electrophoretic determination of glycosylated hemoglobin: effect of variant hemoglobins, hyperlipidemia, and temperature.

We investigated the effect of temperature, variant hemoglobins, and hyperlipidemia on determination of glycosylated hemoglobin by an electrophoretic method (Clin. Chem. 26: 1598-1602, 1980). We found that: (a) temperature variations ranging from 4 to 30 degrees C were without effect on results obtained by electrophoresis; (b) concurrent determination of glycosylated hemoglobin by electrophoresis and column-chromatography in blood specimens from 150 diabetic patients yielded almost identical mean values for both procedures when operations were carried out at 22 degrees C; (c) electrophoretic determination of glycosylated hemoglobin in whole-blood hemolysate was not affected by concentration of triglycerides; and (d) unlike column-chromatographic procedures, which underestimate the percentage of glycosylated hemoglobin in patients with hemoglobin S and C, the electrophoretic method accurately determined the proportion of glycosylated hemoglobin in these hemoglobinopathies. Evidently, electrophoresis on agar gel is an excellent alternative to cation-exchange column-chromatographic methods for glycosylated hemoglobin.