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14-11-2010 | Diabetes | Article

HbA1C measurements misleading during iron, erythropoietin therapy


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MedWire News: UK researchers report that glycated hemoglobin (HbA1C) levels do not accurately reflect the glycemic control of diabetic patients who receive intravenous (iv) iron and erythropoietin-stimulating agents (ESAs) for co-existing chronic kidney disease (CKD).

Indeed, HbA1C levels can fall during treatment with these agents, therefore health professionals should seek out additional methods "for measuring glycemic control such as capillary glucose testing and continuous glucose monitoring (CGM)," say the researchers.

They suggest glycated albumin as a suitable alternative to HbA1C as it reflects glycemic control with similar accuracy in patients with iron deficiency and pre-ESA compared with patients post-therapy.

Jen Ng, from Hull York Medical School, and team studied 30 diabetic patients with moderate to end-stage CKD who underwent iv iron therapy alone (n=15) or with ESA (n=15).

HbA1C levels were measured at baseline and after a mean follow-up period of 16.4 weeks. Seven-point daily glucose was also measured three times a week during the study period along with CGM lasting at least 48 hours on each occasion.

As reported in the journal Diabetes Care, Ng and team found that mean HbA1C levels fell significantly among patients receiving iron alone and among those receiving both agents, from 7.40% and 7.31% at baseline to 6.96% and 6.63% at study end, respectively.

Mean blood glucose, however, did not change significantly among either patient group. Patients taking iron alone had mean blood glucose levels of 9.55 mmol/l at baseline and 9.71 mmol/l at study end, and those taking iron and ESA had blood glucose levels of 8.72 mmol/l at baseline and 8.78 mmol/l at study end.

Both iron and ESA treatment led to significant increases in hemoglobin and hematocrit levels, but this was not associated with the fall in HbA1C levels noted during treatment.

The researchers conclude: "At a time when self-monitoring of blood glucose is being discouraged, especially in non-insulin-treated patients, regular capillary glucose measurements, and the concurrent use of CGM if available, seems essential in order to accurately assess glycemic control in this group of patients."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Lauretta Ihonor

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