Kidney Week

Abstract: SA-PO319

Impact of Carbamylation on the Association of Glycated Albumin and Diabetic Kidney Disease (DKD) Progression

Session Information

• Diabetic Kidney Disease: Clinical Pathology, Diagnostic and Treatment Advances
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Diabetic Kidney Disease

• 702 Diabetic Kidney Disease: Clinical

Authors

• Tang, Mengyao, Massachusetts General Hospital, Boston, Massachusetts, United States

Mengyao Tang, MD, MPH, FASN

• Berg, Anders H., Cedars-Sinai Medical Center, Los Angeles, California, United States

Anders H. Berg, MD, PhD

• Kalim, Sahir, Massachusetts General Hospital, Boston, Massachusetts, United States

Sahir Kalim, MD, MS, MSc, FASN

Background

HbA_1c is widely used to estimate glycemia, yet it is less reliable in CKD due to factors such as anemia and competition from another post-translational protein modification, carbamylation, acting on the same amino groups. We previously showed that the association between HbA_1c and the risk of CKD progression was modified by anemia and carbamylation. While an alternative hemoglobin-independent glycemic marker, glycated albumin, could overcome the anemia-related limitation of HbA_1c, little is known about whether it is impacted by carbamylation in CKD.

Methods

We measured baseline serum glycated albumin and carbamylated albumin levels in 1,550 patients with co-existing CKD and diabetes enrolled in the prospective Chronic Renal Insufficiency Cohort study. A Cox regression model was used to test the association between glycated albumin and CKD progression (ESKD or 50% eGFR decline), with an interaction term of glycated albumin and carbamylated albumin to evaluate whether carbamylation modified this association.

Results

Participant characteristics included mean age 60 (SD 9) years; mean eGFR 38 (15) mL/min/1.73 m²; median glycated albumin 22 (IQR 18-28) %; and median carbamylated albumin 8 (6-11) mmol/mol. Glycated albumin levels were higher in the higher carbamylated albumin quartiles. During a median 7-year follow-up, 805 (51.9%) individuals developed CKD progression. Overall, higher glycated albumin levels (restricted cubic spline or quartiles) were independently associated with greater risks of CKD progression (Fig 1): compared with quartile 1, those in quartile 4 had a 1.35-fold greater risk (95% CI, 1.10 to 1.66). Interaction testing between glycated albumin and carbamylated albumin was not significant (P = 0.43).

Conclusion

In patients with CKD and diabetes, the association between glycated albumin and CKD progression is not modified by carbamylation. This finding suggests that glycated albumin could overcome the carbamylation-related limitation of HbA_1c in CKD.

Fig 1. Adjusted HR for Glycated Albumin and Risks of CKD Progression

Funding

• NIDDK Support