Glycated albumin but not HbA1c reflects glycaemic control in patients with neonatal diabetes mellitus.

AIMS/HYPOTHESIS: It is difficult to use HbA(1c) as an indicator of glycaemic control in patients with neonatal diabetes mellitus (NDM) because of high levels of fetal haemoglobin (HbF) remaining in the blood. In this study, glycated albumin (GA), which is not affected by HbF, and HbA(1c) were compared to evaluate whether they reflect glycaemic control in patients with NDM.

METHODS: This study included five patients with NDM. Age at diagnosis was 38 ± 20 days. Insulin therapy was started in all patients, and levels of GA, HbA(1c) and HbF were measured monthly for 6 months. One-month average preprandial plasma glucose (aPPG) was calculated using self-monitoring of blood glucose.

RESULTS: Plasma glucose and GA were elevated (29.7 ± 13.1 mmol/l [n = 5] and 33.3 ± 6.9% [n = 3], respectively) but HbA(1c) was within normal limits (5.4 ± 2.6% [35.5 ± 4.9 mmol/mol]; n = 4) at diagnosis. With diabetes treatment, aPPG (r = -0.565, p = 0.002), GA (r = -0.552, p = 0.003) and HbF (r = -0.855, p < 0.0001) decreased with age, whereas HbA(1c) increased (r = 0.449, p = 0.004). GA was strongly positively correlated with aPPG (r = 0.784, p < 0.0001), while HbA(1c) showed no correlation with aPPG (r = 0.221, p = 0.257) and was significantly inversely correlated with HbF (r = -0.539, p = 0.004).

CONCLUSIONS/INTERPRETATION: GA is a useful indicator of glycaemic control in patients with NDM, whereas HbA(1c) is influenced by age-related changes in HbF and does not accurately reflect glycaemic control.