Continuous Glucose Monitoring and Glycemic Control in Patients With Type 2 Diabetes Mellitus and CKD

Abstract: Rationale & Objective The accuracy of glycated hemoglobin (HbA1c) for assessment of glycemic control in patients with CKD is uncertain. This study assessed the accuracy of HbA1c using continuous glucose monitoring. Study Design Diagnostic test study of HbA1c and serum fructosamine. The continuous glucose monitor was worn for 14 days. Glucose was measured every 15 minutes (up to 1,344 measurements). Average glucose concentration was calculated for each patient from the patient’s continuous glucose monitor glucose measurements. Linear regression was applied to estimate the relationship between average glucose concentration and HbA1c and serum fructosamine. The influence of patient characteristics on the relationship between HbA1c and average glucose concentration were examined in a multivariate regression model. Setting & Participants: Patients with type 2 diabetes and CKD (eGFR 7-45 ml/min, not on dialysis) seen in an academic nephrology clinic. Tests Analyzed The accuracy of HbA1c for assessment of chronic glycemia. A secondary objective was to study serum fructosamine. Outcomes The degree of correlation between continuous glucose monitoring derived average glucose concentration and HbA1c; serum fructosamine was studied as a secondary outcome. Results 80 patients wore the continuous glucose monitor for a mean of 12.7±2.9 days. The average glucose concentration of all patients was 151.5±55.7 mg/dL. The mean HbA1C was 7.2±1.5%. HbA1c was highly correlated with average glucose concentration, described by the equation average glucose concentration =30.48 x HbA1C - 68.48, r = 0.82, p Limitations Relatively small sample size. Conclusions HbA1c is an accurate measure of glycemic status among patients with CKD and type 2 diabetes. This relationship appears to hold true among patients with more severe CKD.