HbA1c Levels Between 6.7-7.1 Percent May Lower Risks in Severe CKD Patients with Diabetes: Study Shows

"In patients with diabetes and severe CKD, an HbA1c range of 6.7–7.1% was linked to the lowest risk of complications. Risks of cardiovascular events rose at HbA1c ≥7.2% and <5.8%, while hypoglycemia-related hospitalizations increased at ≥6.7%, highlighting 6.7–7.1% as the optimal target range," the researchers reported.

The study explored the association between HbA1c levels and diabetes-related complications in adults with severe CKD, defined as having an estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m². The research team analyzed data from 27,113 patients with diabetes and severe CKD, using data collected between 2010 and 2022 through Danish national health registries. For comparison, two control groups were included—over 80,000 patients each with diabetes and either mild-to-moderate CKD or no-to-mild CKD.

Using multiple Cox regression models, the researchers assessed the risk of major adverse cardiovascular events (MACE), microvascular complications, and hospital admissions due to hypoglycemia across different HbA1c levels.

The following were the key findings of the study:

• There was a U-shaped risk pattern for major adverse cardiovascular events (MACE) in patients with severe CKD.
• MACE risk increased at HbA1c levels below 5.8% (40 mmol/mol) and above 7.2% (55 mmol/mol), compared to those with HbA1c between 6.3–6.6% (45–49 mmol/mol).
• The risk of microvascular complications rose significantly when HbA1c exceeded 7.2%.
• Hospitalization due to hypoglycemia became notably more frequent at HbA1c levels of 6.7% or higher.
• These risk patterns remained consistent when compared with cohorts having mild-to-moderate or no-to-mild CKD.
• The findings highlight that both overly strict and poorly controlled glycemic levels are associated with increased complications.
• Excessively low HbA1c levels may contribute to adverse cardiovascular outcomes, likely due to a higher risk of hypoglycemia.

Based on the study’s findings, maintaining HbA1c between 6.7% and 7.1% (50–54 mmol/mol) may offer the best balance in reducing the risk of both microvascular and macrovascular complications, as well as minimizing hypoglycemia-related hospitalizations.

Given the growing number of patients living with both diabetes and CKD, this research provides timely insights into optimal glycemic targets for long-term safety and improved outcomes.

The authors recommend that treatment goals for patients with severe CKD should consider individual risk profiles and avoid overly aggressive glycemic targets. Further research could help refine personalized treatment strategies and support evidence-based updates to clinical guidelines.

Reference:

Dea H. Kofod, Nicholas Carlson, Thomas P. Almdal, Tobias Bomholt, Christian Torp-Pedersen, Kirsten Nørgaard, Jesper H. Svendsen, Bo Feldt-Rasmussen, Mads Hornum; The Association Between Hemoglobin A1c and Complications Among Individuals With Diabetes and Severe Chronic Kidney Disease. Diabetes Care 2025; dc250339. https://doi.org/10.2337/dc25-0339