The Glycemic Indices in Dialysis Evaluation (GIDE) study: Comparative measures of glycemic control in diabetic dialysis patients.

The validity of hemoglobin A1c (HgbA1c) is undergoing increasing scrutiny in the advanced CKD/ESRD (chronic kidney disease/end-stage renal disease) population, where it appears to be discordant from other glycemic indices. In the Glycemic Indices in Dialysis Evaluation (GIDE) Study, we sought to assess correlation of HgbA1c with casual glucose, glycated albumin, and serum fructosamine in a large group of diabetic patients on dialysis. From 26 dialysis facilities in the United States, 1758 diabetic patients (hemodialysis = 1476, peritoneal dialysis = 282) were enrolled in the first quarter of 2013. The distributions of HgbA1c and the other glycemic indices were analyzed. Intra-patient coefficients of variation and correlations among the four glycemic indices were determined. Patients with low HgbA1c values were both on higher erythropoietin (ESA) doses and more anemic. Serum glucose exhibited the highest intra-patient variability over a 3-month period; variability was modest among the other glycemic indices, and least with HgbA1c. Statistical analyses inclusive of all glycemic markers indicated modest to strong correlations. HgbA1c was more likely to be in the target range than glycated albumin or serum fructosamine, suggesting factors which may or may not be directly related to glycemic control, including anemia, ESA management, and iron administration, in interpreting HgbA1c values. These initial results from the GIDE Study clarify laboratory correlations among glycemic indices and add to concerns about reliance on HgbA1c in patients with diabetes and advanced kidney disease.