Glycated Albumin and Adverse Clinical Outcomes in Patients With CKD: A Prospective Cohort Study

Abstract

Rationale & objective: Hemoglobin A_1c (HbA_1c) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown.

Study design: Prospective cohort study.

Setting & participants: 3,110 participants with CKD from the Chronic Renal Insufficiency Cohort study.

Exposure: Baseline GA levels.

Outcome: Incident end-stage kidney disease (ESKD), cardiovascular disease (CVD) events, and all-cause mortality.

Analytical approach: Cox proportional hazards regression.

Results: Participant characteristics included mean age 59.0±10.8 SD years; 1,357 (43.6%) female; and 1,550 (49.8%) with diabetes. The median GA was 18.7% (IQR, 15.8%-23.3%). During an average 7.9-year follow-up, there were 980 ESKD events, 968 CVD events, and 1,084 deaths. Higher GA levels were associated with greater risks of all outcomes, regardless of diabetes status: hazard ratios for ESKD, CVD, and death among participants with the highest quartile compared with quartile 2 (reference) were 1.42 (95% CI, 1.19-1.69), 1.67 (95% CI, 1.39-2.01), and 1.63 (95% CI, 1.37-1.94), respectively. The associations with CVD and death appeared J-shaped, with increased risk also seen at the lowest GA levels. Among patients with coexisting CKD and diabetes, the associations of GA with outcomes remained significant even after adjusting for HbA_1c. For each outcome, we observed a significant increase in the fraction of new prognostic information when both GA and HbA_1c were added to models.

Limitations: Lack of longitudinal GA measurements; and HbA_1c measurements were largely unavailable in participants without diabetes.

Conclusions: Among patients with CKD, GA levels were independently associated with risks of ESKD, CVD, and mortality, regardless of diabetes status. GA added prognostic value to HbA_1c among patients with coexisting CKD and diabetes.

Plain-language summary: Hemoglobin A_1c (HbA_1c) is widely used to estimate glycemia, yet it is less reliable in patients with chronic kidney disease (CKD). There is growing interest in the complementary use of glycated albumin (GA) to improve glycemic monitoring and risk stratification. However, whether GA associates with clinical outcomes in a non-dialysis-dependent CKD population remains unknown. In this cohort study of 3,110 individuals with non-dialysis-dependent CKD, GA levels were independently associated with risks of end-stage kidney disease, cardiovascular disease (CVD), and mortality. The associations with CVD and mortality appeared to be J-shaped. Among patients with coexisting CKD and diabetes, GA added prognostic value to HbA_1c. Thus, GA may be a valuable complementary test to HbA_1c in patients with CKD.

Keywords: Chronic kidney disease; clinical epidemiology; diabetes mellitus; glycated albumin.