Little is known about the predictive value of glycosylated hemoglobin (HbA1C) variability in patients with advanced chronic kidney disease (CKD). The aim of this study was to investigate whether HbA1C variability is associated with progression to end-stage renal disease in diabetic patients with stages 3⁻5 CKD, and whether different stages of CKD affect these associations. Three hundred and eighty-eight patients with diabetes and stages 3⁻5 CKD were enrolled in this longitudinal study. Intra-individual HbA1C variability was defined as the standard deviation (SD) of HbA1C, and the renal endpoint was defined as commencing dialysis. The results indicated that, during a median follow-up period of 3.5 years, 108 patients started dialysis. Adjusted Cox analysis showed an association between the highest tertile of HbA1C SD (tertile 3 vs. tertile 1) and a lower risk of the renal endpoint (hazard ratio = 0.175; 95% confidence interval = 0.059⁻0.518; p = 0.002) in the patients with an HbA1C level ≥ 7% and stages 3⁻4 CKD, but not in stage 5 CKD. Further subgroup analysis showed that the highest two tertiles of HbA1C SD were associated with a lower risk of the renal endpoint in the group with a decreasing trend of HbA1C. Our results demonstrated that greater HbA1C variability and a decreasing trend of HbA1C, which may be related to intensive diabetes control, was associated with a lower risk of progression to dialysis in the patients with stages 3⁻4 CKD and poor glycemic control (HbA1c ≥ 7%).
Keywords: HbA1C variability; chronic kidney disease; end-stage renal disease.