Estimating Glycemia from HbA1c and CGM: Analysis of Accuracy and Sources of Discrepancy

• DOI: 10.2337/figshare.24852888.v1
• Publication Date: 2024-02-23T01:05:49Z
• Authors: Veronica Tozzo; Matthew Genco; Shammah Omololu; Christopher Mow; Hasmukh R. Patel; Chhaya H. Patel; Samantha N. Ho; Ngoc Thi Dang Lam; Batoul Abdulsater; Nikita Patel; Robert M. Cohen; David M. Nathan; Camille E. Powe; Deborah J. Wexler; John M. Higgins
• Keywords: Adult; Glycated Hemoglobin; Blood Glucose; Diabetes Mellitus, Type 1; 0302 clinical medicine; Blood Glucose Self-Monitoring; Humans; Original Article; Retrospective Studies

<p dir="ltr">Objective. To examine the accuracy of different periods continuous glucose monitoring (CGM), hemoglobin A1c (HbA1c), and their combination for estimating mean glycemia over 90 days (AG90).</p><p dir="ltr">Research Design Methods. We retrospectively studied 985 90-day CGM with <10% missing data from 315 adults (86% type 1 diabetes) paired HbA1c measurements. The impact red blood cell age as a proxy non-glycemic effects on was estimated using published theoretical models compared empirical data. Given lack gold standard measurement AG90, we applied correction methods to generate reference (eAG90) that used assess CGM. </p><p dir="ltr">Results. Using 14 at end period resulted in absolute error [95th percentile] [34] mg/dL eAG90. two non-overlapping 14-day reduced 6 [15] mg/dl. Non-glycemic led average calculated 12 [29] mg/dL. Combining 10 [26] Mismatches between greater than 40 occurred more 5% time.</p><p dir="ltr">Conclusions. estimates eAG90 limited can be improved by averaging or extending beyond 26 days. Large mismatches are not unusual may persist due stable factors.</p>