Variability in glycated albumin levels predicts the progression of diabetic nephropathy

Aim The present study was performed to assess variability in glycated albumin (GA) using a coefficient of variation (CV) to predict the progression of diabetic nephropathy in type 2 diabetic patients, independently of HbA1c and other conventional risk factors. Methods The present study consecutively enrolled 369 patients with type 2 diabetes mellitus from outpatient clinic. During the follow-up period, GA and HbA1c levels were measured repeatedly (≥5 times), and the CV of GA (GA-CV) was calculated for each patient. The patients were divided into two subgroups: Group 1, a MEAN-HbA1c value <7.2% (55mmol/mol); Group 2, a MEAN-HbA1c value ≥7.2% (55mmol/mol). The primary outcome was the renal composite outcome (RCO), which was based on the progression rates of chronic kidney disease and albuminuria and renal death. Results The median follow-up period was 33months. The RCO was developed in 109 patients (29.5%). In Group 1, the third highest and highest quartile groups for GA-CV had higher cumulative incidences of the RCO than those of the lowest quartile group (Q4 vs. Q1: HR=5.43, P=0.007, Q3 vs. Q1: HR=5.16, P=0.009). After adjusting for HbA1c levels and other risk factors, the GA-CV remained significantly associated with the development of the RCO. However, Group 2 did not exhibit any significant differences in terms of the cumulative incidence of the RCO among the four GA-CV quartile groups. Conclusions The present findings suggest that variability in GA may be a better predictor of the progression of diabetic nephropathy in type 2 diabetic patients regardless of HbA1c.