Association of HbA 1C Variability and Renal Progression in Patients with Type 2 Diabetes with Chronic Kidney Disease Stages 3⁻4.

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%).