The effect of iron and erythropoietin treatment on the A1C of patients with diabetes and chronic kidney disease.

OBJECTIVE: To examine the effect of intravenous iron and erythropoietin-stimulating agents (ESAs) on glycemic control and A1C of patients with diabetes and chronic kidney disease (CKD).

RESEARCH DESIGN AND METHODS: This was a prospective study of patients with type 2 diabetes and CKD stage IIIB or IV undergoing intravenous iron (group A) and/or ESA (group B). Full blood profiles were determined over the study period. Glycemic control was monitored using A1C, seven-point daily glucose three times weekly, and continuous glucose monitoring (CGM).

RESULTS: There were 15 patients in both group A and group B. Mean A1C (95% CI) values fell in both groups (7.40% [6.60-8.19] to 6.96% [6.27-7.25], P<0.01, with intravenous iron and 7.31% [6.42-8.54] to 6.63% [6.03-7.36], P=0.013, ESA). There was no change in mean blood glucose in group A (9.55 mmol/l [8.20-10.90] vs. 9.71 mmol/l [8.29-11.13], P=0.07) and in group B (8.72 mmol/l [7.31-10.12] vs. 8.78 mmol/l [7.47-9.99], P=0.61) over the study period. Hemoglobin and hematocrit values significantly increased following both treatments. There was no linear relationship found between the change in A1C values and the rise of hemoglobin following either treatment.

CONCLUSIONS: Both iron and ESA cause a significant fall in A1C values without a change to glycemic control in patients with diabetes and CKD. At the present time, regular capillary glucose measurements and the concurrent use of CGM remain the best alternative measurements of glycemic control in this patient group.