Hemoglobin A 1c in Hemodialysis Patients Source: Ix JH. Hemoglobin A1c in hemodialysis patients: Should one size fit all? Clin J Am Soc Nephrol. 2010;5:1539–1541.

Overview Diabetes mellitus is one of the major causes behind endstage renal disease (ESRD) in the United States. It has been observed that, on average, four out of ten patients seen on dialysis rounds has diabetes mellitus, among whom the levels of hemoglobin A1c (HbA1c) are frequently measured quarterly. At present, the kidney disease: Improving Global Outcomes foundation does not offer clinical practice guidelines for HbA1c management. According to the kidney disease outcomes quality initiative (KDOQI) recommendations (updated in 2007), “Target HbA1c for people with diabetes should be <7%, irrespective of the presence or the absence of chronic kidney disease.” This recommendation aligns with the diabetes management in the general population.

Recent data across randomized studies on statins provides caution about the extension of data from the general population to ESRD, including therapies with significant established benefits in the general population. There have also been heightened concerns regarding the association of drugs used for treating diabetes in ESRD patients, with the risk of cardiovascular disease events.

A study was conducted evaluating the link between HbA1c levels and mortality in hemodialysis patients with diabetes. The observed HbA1c levels were less than KDOQI recommendations. The association of HbA1c with mortality differed significantly with the adjustment for demographic and confounding variables. The unadjusted analyses showed that patients with HbA1c levels between 7 and 9% had the least overall mortality, and those with HbA1c levels <5% had the greatest mortality. Similar results were observed in another study; however, patients with HbA1c levels <5% or 7% showed statistically significantly higher risk of mortality than individuals with intermediate HbA1c levels.

Through a post hoc analysis of the 4-D study it was shown that higher HbA1c levels were related with sudden death but not myocardial infarction or stroke. Hemoglobin A1c values <7% were similarly linked with an average level of blood glucose in ESRD as in the general population, however, in the ESRD patients, at higher levels, the average serum glucose levels were lesser at any given HbA1c. Some other small studies have shown that HbA1c remains associated with fasting and post challenge glucose levels in ESRD; however, the correlations are not so significant than those observed in the general population.

Conclusion Several important aspects are required to be addressed to support HbA1c in dialysis patients. The control of HbA1c can influence the risk of peripheral arterial disease and amputation, an extremely common and morbid event seen in ESRD patients. Glycemic control may affect the patency of permanent dialysis access and the risk of infection. Tighter control might reduce the development of neuropathy and retinopathy in ESRD as observed in the general population. Proper assessment of association of HbA1c with these outcomes in ESRD patients should be considered for future research to find the risks and benefits linked with various HbA1c targets. Individualized HbA1c targets with the consideration of the extent of life expectancy, age, comorbidity and the patient’s ability and their caregivers to act in response to hypoglycemic events might be more accurate than a “one size fits all” target designed using studies in the general population.

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