Is a Target Hemoglobin A1c Below 7% Safe in Dialysis Patients?

The KDOQI Clinical Practice Guidelines and Clinical Practice Recommendations for Diabetes for Chronic Kidney Disease Section 2.1 states that the “[t]arget HbA1c [hemoglobin A1c] for people with diabetes should be < 7.0%, irrespective of the presence or absence of CKD [chronic kidney disease].”1 This statement refers to the current recommendations from the American Diabetes Association (ADA), and is supported by multiple randomized, interventional trials of patients with mostly intact renal function, and observational studies in patients on dialysis. However, the text also addresses several caveats, such as the absence of prospective studies demonstrating the clinical benefit of such an aggressive HbA1c target in dialysis patients, and the unclear correlation between HbA1c levels and the ambient glucose concentrations. In addition, there may be a significant increased risk (up to 5-fold) of hypoglycemia in patients with kidney disease treated with insulin.1 Finally, a recently published observational study using the large Fresenius database2 did not show an association between HbA1c levels and 12-month survival over a large range of values.

The current evidence appears to question the relevance of HbA1c monitoring in dialysis patients, and highlights the risks of therapy to achieve an aggressive HbA1c target. Both the ADA and the Department of Veterans Affairs guidelines3 for the management of diabetes recommend less stringent targets for patients with a severe comorbid condition, with the Veterans Administration specifying a goal below 9%. How did these considerations impact the decision by the KDOQI committee to support the application of the ADA guidelines in these patients?

We suspect that these issues will garner more attention with the development and propagation of clinical performance measures, and are concerned that clinical practice may move toward unproven goals under the guise of evidence-based care.