6547 Glycated Hemoglobin is a Better Glycemic Indicator than Glycated Albumin in Mothers with Pregestational Diabetes: Preliminary Results of a CGM study in the 2nd and 3rd Trimesters
Authors: Amin Md Syazwan Md , Ratnasingam Jeyakantha , Paramasivam Sharmila Sunita , Ibrahim Luqman , Lim Lee Ling , Lim Quan Hziung , Hee Ken Yoong Nicholas , Hamdan Mukhri , Ganapathy Shubash , Sthaneshwar Pavai , Vethakkan Shireene Ratna 
Published: October 2024

Abstract
Disclosure: M. Md Amin: None. J. Ratnasingam: None. S.S. Paramasivam: None. L. Ibrahim: None. L. Lim: None. Q. Lim: None. N. Hee Ken Yoong: None. M. Hamdan: None. S. Ganapathy: None. P. Sthaneshwar: None. S.R. Vethakkan: None.
Glycemic control is strongly associated with maternofetal outcomes in mothers with pregestational diabetes. Glycated Hemoglobin (HbA1c) is most accurate in the first trimester. The use of HbA1c to monitor glycemia in pregnancy however is controversial, as altered red-cell kinetics and iron deficiency render it less accurate than in the nongravid state, especially in the 2nd or 3rd trimester. Glycated albumin (GA) is an alternative measure of intermediate-term glycemia (2-3 weeks) which is unaffected by red-cell survival that has been used to monitor glycemia in CKD and pregnancy. However, the accuracy of HbA1c as opposed to GA is unclear, especially in later pregnancy and there are no published data comparing it with CGM (Continuous Glucose Monitoring) metrics in pregnancy. We compared the accuracy of HbA1c and GA as a glycemic indicator in later pregnancy using mean glucose from a 6-day CGM as reference, hypothesizing that GA would correlate more strongly with CGM metrics.Twelve pregnant Malaysian mothers with pregestational Type 1 (n=2) and Type 2 DM(n=10) were enrolled in this prospective observational study. Mothers with known hemoglobinopathy, nephrotic syndrome and liver cirrhosis were excluded. Patients underwent blinded 6-day CGM (Medtronic iPro2) followed by blood sampling for GA, HbA1c, albumin and hemoglobin on Day 7 at standardized timepoints in the 2nd and 3rd trimester (20-28 weeks, 30-36 weeks). Mean pre-pregnancy BMI was 28kg/m2(±5). Mean Hb was 12.3g/dL (±1.5), 16.7% of mothers had anemia, while 62.5% had serum albumin &lt; 35g/L. GA did not correlate with mean CGM glucose (2nd trimester: r=0.180 [n=10], 3rd trimester r=0.493 [n=8], p=NS). After excluding obese women (pre-pregnancy BMI&gt;30kg/m2) however, GA correlated well with mean CGM glucose in the 3rd trimester (r=0.870, p&lt;0.05). HbA1c correlated significantly and strongly with mean CGM glucose in later pregnancy (2nd trimester: r=0.621 [n=11], 3rd trimester r=0.718[n=8], p&lt;0.05) and correlated with estimated A1c from CGM (r=0.548, p=0.01). Unexpectedly, our data indicate that HbA1c correlates well with gold standard mean CGM glucose with a strength approximating that observed in the nongravid population with diabetes, thus validating its use as a complementary secondary measure of glycemia to fingerstick-glucose for therapeutic decision-making in later, as well as early pregnancy. Obesity is a known confounder of accuracy of GA, our findings corroborate this. Therefore, utility of GA as an alternative glycemic measure in pregnancy is potentially limited by the increasing prevalence of obesity worldwide and impact of gestational weight gain. A larger sample is needed to confirm these preliminary findings.
Presentation: 6/2/2024