Glycemic Control and Mortality in Diabetic Patients Undergoing Hemodialysis: Much More to Learn

Distinct biomarker roles for HbA1c and glycated albumin in patients with type 2 diabetes on hemodialysis

AIMS

HbA_1c and glycated albumin (GA) are used to monitor glycemia, but their accuracy to represent glycemic profiles in hemodialysis remains controversial.

METHODS

Continuous glucose monitoring in 97 patients with type 2 diabetes (41 on hemodialysis [HD] and 56 without nephropathy) was analyzed to evaluate whether HbA_1c and/or GA serve as appropriate glycemic profile markers.

RESULTS

The average glucose significantly correlated with HbA_1c in both HD group and group without nephropathy (r=0.59, P<0.0001; r=0.40, P<0.005). The slopes of linear regression lines were statistically indistinguishable (F=0.30, P=0.744), while the y-intercepts were significantly different (F=57.86, P<0.0001). GA showed strong correlation with the glycemic standard deviation (r=0.68, P<0.0001), and with the average glucose (r=0.42, P<0.001). Least square analysis revealed that only HbA_1c, but not GA, was significantly associated with the average glucose (F=10.20, P<0.0005; F=0.38, P=0.5427), while only GA was significantly associated with the glycemic variability in HD group.

CONCLUSIONS

In HD participants, HbA_1c correlates with the average glucose more than GA, but underestimates it, and a correction formula of HbA1c can be developed as an appreciable marker. GA value itself reflects the average glucose, but less accurately than HbA_1c, while it could serve as an indicator for hyperglycemia/hypoglycemia excursion.

[Significance of hemoglobin A1C in the management of diabetes in dialysis patients]

According to latest guidelines hemoglobin A1C plays a central role in the diagnosis of diabetes mellitus. It is well-known from epidemiologic studies that a high rate of diabetic patients enters into dialysis programs and these patients have an unfavourable mortality outcome. Based on surveys conducted in recent years in this patient group, hemoglobin A1C has an important role in assessing carbohydrate metabolism. However, there are several factors independent of blood glucose may affect hemoglobin A1C values both in hemodialysis and peritoneal dialysis patients. Hemodialysis disturbs hemoglobin A1c assessment because of an accelerated turnover of lost red blood cells. During peritoneal dialysis a considerable amount of glucose may be absorbed from the peritoneal solutions that may influence hemoglobin A1C level. Several alternative markers such as glycated albumin and fructosamine have been evaluated but they failed to have prognostic advantage. It has been concluded that among dialysis patients the hemoglobin A1C range between 6.5 and 8% is associated with the lowest mortality risk.