Glycated hemoglobin and glycated albumin in patients with diabetes undergoing hemodiafiltration

Background Online hemodiafiltration (OHDF), which results in high albumin leakage, is now widely used in Japan for dialysis, since the national insurance system began reimbursing its costs in 2012. Glycated albumin (GA) levels are affected by albumin leakage into effluent dialysate fluid. Therefore, GA levels in patients requiring diabetes-related dialysis undergoing OHDF require monitoring. However, there have been no previous reports on glycemic control indicators of patients with diabetes undergoing OHDF. We aimed to develop a glycemic control index for patients requiring diabetes-related dialysis undergoing OHDF. Methods This study comprised 133 diabetic patients undergoing OHDF. We examined the correlation between GA and glycated hemoglobin (HbA1c) levels. We analyzed effluent dialysate fluid samples from 41 patients classified into 3 groups, namely, group A, non-protein-leaking OHDF (n = 20); group B, protein-leaking OHDF (n = 14); and group C, highly efficient protein-leaking OHDF (n = 7). We examined the association between GA and HbA1c levels in each group and among patients. Results A significant positive correlation was observed between GA and HbA1c levels (r = 0.562, p < 0.0001). There was no significant correlation between pre-dialysis blood glucose levels and HbA1c or GA levels as observed on regular blood tests performed under non-fasting conditions. Patients were classified into 2 groups based on their mean albumin levels (3.4 g/dL cutoff). The correlation between HbA1c and GA levels was found to be weaker in the 51 patients with mean albumin levels < 3.4 g/dL (r = 0.399, p = 0.0037) than in the 82 patients with mean albumin levels >= 3.4 g/dL (r = 0.674, p < 0.0001). When the hemodiafilter performance was assessed, no correlation was observed between HbA1c and GA levels in group C patients. Conclusions GA levels may be underestimated in patients undergoing OHDF because of the effect of albumin leakage into the effluent dialysate fluid. If a stable hemoglobin value can be maintained during OHDF therapy, then GA and HbA1c levels should be used as a glycemic control index for patients requiring diabetes-related dialysis, considering the dialysis treatment method and protein permeability of the dialyzers and hemodiafilters.