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Diabetes

Poster Session 1

(176) Continuous glucose monitoring metrics and perinatal morbidity in pregnancies with type 1 diabetes

Tuesday, February 13, 2024
10:30 AM – 12:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective:

To examine the discriminatory ability of continuous glucose monitoring (CGM) metrics (time-in-range, TIR; time-above-range, TAR; time-below-range, TBR; glycemic variability, GV) across gestation and hemoglobin A1c (HbA1c), for adverse perinatal outcomes (APOs) in pregnant people with type 1 diabetes (T1DM).

Study Design: This is a retrospective study (2019-22) of gravidas with T1DM using CGM with target range 70-140 mg/dl. Exposures were average TIR, TAR, TBR, GV, and HbA1c per trimester. Primary maternal and neonatal outcomes were hypertensive disorders of pregnancy (HDP) and large-for-gestational age neonate (LGA, birthweight ≥ 90%ile). Secondary neonatal outcomes were neonatal intensive care unit (NICU) admission, neonatal hypoglycemia (NH, glucose ≤ 40 mg/dl in first 24 hours), and jaundice (requiring phototherapy). The Mann-Whitney U test compared median CGM metrics and HbA1c by outcome each trimester. Receiver operating characteristic (ROC) analysis determined the optimal cut-point with the greatest sensitivity and specificity and area under the curve (AUC) for each metric.

Results:

Among 92 patients using CGM for T1DM, the majority were multiparous (58%) and used insulin pumps (60%). Pregnancies with HDP, NICU admission, and jaundice had lower TIR each trimester (p ≤ 0.01); lower TIR was associated with LGA only in the first trimester (p=0.01). Pregnancies with (vs. without) HDP (41% vs. 28%), LGA (36% vs. 27%), NICU admission (46% vs. 30%), and jaundice (46% vs. 29%) had higher median TAR in the first trimester (p ≤ 0.01), with similar findings in the 2nd and 3rd trimester (p < 0.05). Median HbA1c was also higher every trimester for those with HDP, LGA, NICU admission, and jaundice (p < 0.05). For NH, we did not identify a difference in CGM metrics or HbA1c. Among CGM metrics, TAR had the greatest discriminatory ability for APOs (AUC 0.63-0.90, Table), but its discriminatory ability was similar to that of HbA1c for HDP, LGA and NICU across gestation.

Conclusion:

TIR is inversely associated with APOs in people with T1DM, but has poor discriminatory ability for APOs compared to TAR and HbA1c.