Comparison of Glycated Albumin and Hemoglobin A1c Concentrations in Diabetic Subjects on Peritoneal and Hemodialysis

Abstract

Background Relative to hemoglobin A1c (HbA1c), percentage of glycated albumin (GA%) more accurately reflects recent glycemic control in diabetic hemodialysis (HD) patients. Methods To determine the accuracy of glycemic assays in a larger sample including patients on peritoneal dialysis (PD), HbA1c and GA% were measured in 519 diabetic subjects: 55 on PD, 415 on HD, and 49 non-nephropathy controls. Results Mean ± SD serum glucose levels were higher in HD and PD patients relative to non-nephropathy controls (HD 169.7 ± 62 mg/dL, PD 168.6 ± 66 mg/dL, controls 146.1 ± 66 mg/dL; p = 0.03 HD vs controls, p = 0.13 PD vs controls). GA% was also higher in HD and PD patients (HD 20.6% ± 8.0%, PD 19.0% ± 5.7%, controls 15.7% ± 7.7%; p < 0.02 HD vs controls and PD vs controls). HbA1c was paradoxically lower in dialysis patients (HD 6.78% ± 1.6%, PD 6.87% ± 1.4%, controls 7.3% ± 1.4%; p = 0.03 HD vs controls, p = 0.12 PD vs controls). The serum glucose/HbA1c ratio differed significantly between dialysis patients and controls ( p < 0.0001 HD vs controls, p = 0.002 PD vs controls), while serum glucose/GA% ratio was similar across groups ( p = 0.96 HD vs controls, p = 0.64 PD vs controls). In best-fit multivariate models with HbA1c or GA% as outcome variable, dialysis status was a significant predictor of HbA1c but not GA%. Conclusions The relationship between HbA1c and GA% differs in diabetic patients with end-stage renal disease who perform either PD or HD compared to those without nephropathy. HbA1c significantly underestimates glycemic control in peritoneal and hemodialysis patients relative to GA%.