THE IMPACT OF CHRONIC KIDNEY DISEASE AND ANEMIA ON THE ASSOCIATION BETWEEN FASTING PLASMA GLUCOSE AND HBA1C LEVELS
Author(s)
Galia Zacay, MPH, MD1, Neora Alterman, PhD2, Noga Fallach, Msc3, Victor Gross, BSc4, Gabriel Chodick, PhD5, Anthony Heymann, BSC MBBS MHA4;
1Meuhedet Health Services, Tel-Aviv, Israel, 2Meuhedet Health Services, Hod-Hasharon, Israel, 3Meuhedet health Services, Alei Zahav, Israel, 4Meuhedet Health Services, Tel Aviv, Israel, 5Tel Aviv University, Tel Aviv, Israel
1Meuhedet Health Services, Tel-Aviv, Israel, 2Meuhedet Health Services, Hod-Hasharon, Israel, 3Meuhedet health Services, Alei Zahav, Israel, 4Meuhedet Health Services, Tel Aviv, Israel, 5Tel Aviv University, Tel Aviv, Israel
OBJECTIVES: HbA1c is widely used to monitor long‑term glycemic control, however, its validity is reduced in chronic kidney diseases (CKD), where factors such as anemia alter the relationship between glycation and glucose exposure. As CKD progresses, HbA1c levels may be falsely decreased, weakening their correlation with fasting glucose. Because clinical guidelines often rely on specific HbA1c thresholds, these inaccuracies may contribute to suboptimal medication management, treatment delays, and increased risk of complications.
The aim of this study is to characterize how the correlation between fasting glucose and HbA1c changes across CKD stages in patients with and without anemia.
METHODS: We conducted a cross‑sectional study using computerized data from a large health maintenance organization, including all adults with type 2 diabetes. CKD stage was defined by estimated glomerular filtration rate (eGFR). Anemia was defined as hemoglobin <12g/dL in women and <13g/dL in men. Linear regression models and Pearson correlation coefficients were used to assess the relationship between fasting glucose and HbA1c across CKD stages, stratified by anemia status.
RESULTS: The study included 69,564 adults with diabetes, of whom 17.9% had eGFR<60 mL/min/1.73m². Among patients with eGFR≥60 and no anemia, HbA1c increased by 0.023 percentage points for each 1mg/dL increase in fasting glucose. This slope decreased to 0.020 for those with eGFR 45-59 without anemia, 0.018 for those with anemia, and 0.011 for patients with eGFR <15. Correlation between fasting glucose and HbA1c was high in patients with eGFR ≥60 and no anemia (R=0.73, 95% CI 0.73-0.74) and declined with worsening CKD and anemia: r=0.64 (0.62-0.65) and r=0.57 (0.24-0.60) for eGFR 45-59 without and with anemia, respectively, and R=0.55 (0.48-0.62) for eGFR <15 with anemia.
CONCLUSIONS: HbA1c is less reliable as kidney function declines, and anemia further reduces its correlation with fasting glucose. Clinicians should interpret HbA1c cautiously in CKD to avoid undertreatment and prevent complications.
The aim of this study is to characterize how the correlation between fasting glucose and HbA1c changes across CKD stages in patients with and without anemia.
METHODS: We conducted a cross‑sectional study using computerized data from a large health maintenance organization, including all adults with type 2 diabetes. CKD stage was defined by estimated glomerular filtration rate (eGFR). Anemia was defined as hemoglobin <12g/dL in women and <13g/dL in men. Linear regression models and Pearson correlation coefficients were used to assess the relationship between fasting glucose and HbA1c across CKD stages, stratified by anemia status.
RESULTS: The study included 69,564 adults with diabetes, of whom 17.9% had eGFR<60 mL/min/1.73m². Among patients with eGFR≥60 and no anemia, HbA1c increased by 0.023 percentage points for each 1mg/dL increase in fasting glucose. This slope decreased to 0.020 for those with eGFR 45-59 without anemia, 0.018 for those with anemia, and 0.011 for patients with eGFR <15. Correlation between fasting glucose and HbA1c was high in patients with eGFR ≥60 and no anemia (R=0.73, 95% CI 0.73-0.74) and declined with worsening CKD and anemia: r=0.64 (0.62-0.65) and r=0.57 (0.24-0.60) for eGFR 45-59 without and with anemia, respectively, and R=0.55 (0.48-0.62) for eGFR <15 with anemia.
CONCLUSIONS: HbA1c is less reliable as kidney function declines, and anemia further reduces its correlation with fasting glucose. Clinicians should interpret HbA1c cautiously in CKD to avoid undertreatment and prevent complications.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
CO49
Topic
Clinical Outcomes
Topic Subcategory
Clinical Outcomes Assessment
Disease
SDC: Diabetes/Endocrine/Metabolic Disorders (including obesity), SDC: Urinary/Kidney Disorders