LONG-TERM ASSESSMENT OF GLUCOSE CONTROL BY HEMOGLOBIN-AGE MEASUREMENT

Background Control of blood glucose is important in reducing both the incidence and the severity of complications in diabetes mellitus. One consequence of long-term. hyperglycaemia is the formation and accumula tion of advanced glycation end-products (AGEs) on tissue macromolecule s. An AGE-modified form of human haemoglobin (Hb-AGE), present at high levels in the red cells of diabetic patients, differs from the glucos e-derived Amadori product HbA(1c) in being chemically irreversible and thus persisting for the circulating life of the red cell. We therefor e compared Hb-AGE with HbA(1c) as indicators of long-term blood glucos e control. Methods In an open study we measured circulating HbA(1c) an d Hb-AGE concentrations in eight patients with poorly controlled non-i nsulin-dependent diabetes after a switch to subcutaneous insulin thera py and careful blood glucose monitoring. Results After 16 weeks of ins ulin therapy, the mean HbA(1c) had decreased from 13.3 (SD 1.2) to 7.3 (0.9)% and the mean Hb-AGE from 12.1 (1.5) to 7.3 (1.3) U/mg Hb. The rate of Hb-AGE decline was 23% slower than that of HbA(1c) (p=0.044). Interpretation The observation that Hb-AGE declines more slowly than H bA(1c) is consistent with the irreversible nature of the AGE product. Because of this property, Hb-AGE may prove superior to HbA(1c) as a lo ng-term index of circulating glucose concentrations.