ABSTRACT
BACKGROUND: Relative to hemoglobin A(1c) (HbA(1c)), glycated albumin (GA) more accurately reflects recent glycemic control in diabetic patients on hemodialysis and peritoneal dialysis. These assays have yet to be compared in patients with advanced chronic kidney disease (CKD). METHODS: HbA(1c) and GA were simultaneously measured in 303 diabetic subjects: 70 with CKD prior to dialysis (CKD-stage 4), 184 with CKD after transplantation (TXP-stage 3) and 49 non-nephropathy controls. RESULTS: Mean estimated GFR was 76, 46 and 26 ml/min in controls, TXP-3 and CKD-4 cases, respectively. Mean (SD) HbA(1c) (%) and GA (%) concentrations were 7.30 (1.40) and 16.8 (4.9) in controls, 7.28 (1.66) and 21.5 (6.4) in CKD-4 cases, and 7.21 (1.62) and 21.2 (5.5) in TXP-3 cases, respectively. The GA:HbA(1c) ratio differed significantly between non-nephropathy controls and both groups of CKD patients (both p < 0.001), but not between CKD-4 and TXP-3 cases (p = 0.92). The glucose:HbA(1c) ratio was inversely associated with GFR in all 254 nephropathy cases (r = -0.13; p = 0.04), while glucose:GA did not vary significantly based upon GFR (r = -0.08; p = 0.24). CONCLUSIONS: The relationship between glycated albumin and HbA(1c) is influenced by the presence of reduced GFR in diabetic patients with CKD. The accuracy of the HbA(1c) assay in diabetic subjects with severe nephropathy requires further investigation, although HbA(1c) performs relatively well with milder CKD.
Subject(s)
Diabetes Complications/blood , Diabetes Mellitus/blood , Glycated Hemoglobin/biosynthesis , Hyperglycemia/blood , Hyperglycemia/complications , Kidney Failure, Chronic/blood , Kidney Failure, Chronic/complications , Serum Albumin/biosynthesis , Aged , Female , Glomerular Filtration Rate , Glycation End Products, Advanced , Humans , Hypoglycemic Agents , Kidney Transplantation/methods , Male , Middle Aged , Models, Biological , Glycated Serum AlbuminABSTRACT
BACKGROUND: Relative to hemoglobin A(1c) (HbA(1c)), 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), HbA(1c) 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). HbA(1c) 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/HbA(1c) 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 HbA(1c) or GA% as outcome variable, dialysis status was a significant predictor of HbA(1c) but not GA%. CONCLUSIONS: The relationship between HbA(1c) and GA% differs in diabetic patients with end-stage renal disease who perform either PD or HD compared to those without nephropathy. HbA(1c) significantly underestimates glycemic control in peritoneal and hemodialysis patients relative to GA%.