Glucose Management Indicator may better reflect glycaemic control than HbA1c in early pregnancy, study shows
Further investigation into the relationship between Time in Range and the Glucose Management Indicator (GMI) must be carried out to see how GMI may affect maternal and fetal complications in pregnant women with type 1 diabetes, researchers have said.
An American study, led by Dr Sarit Polsky from the University of Colorado Anschutz Medical Center, set out to explore the relationship between Time in Range (TIR), HbA1c, and the Glucose Management Indicator in pregnancies complicated by type 1 diabetes.
The team examined the continuous glucose monitoring (CGM) data from 27 women with type 1 diabetes throughout pregnancy. Up to 90 days of CGM data were correlated with point-of-care HbA1c levels measured at each trimester, and models were used to compare TIR, HbA1c, and GMI by each trimester.
They reported the following results: “There was a significant negative correlation between TIR and HbA1c; each 10% increase in TIR was associated with a 0.3% reduction in HbA1c. The correlation between TIR and HbA1c was stronger (r = −0.8) during the second and third trimesters than during the first trimester (r = −0.4). There was good correlation between TIR and GMI during each trimester (r = 0.9 for each trimester). The relationship between GMI and HbA1c especially during second (r = 0.8) and third trimesters (r = 0.8) was strong.”
The researchers went on to conclude: “In the first trimester, the correlation between HbA1c level and TIR was relatively small, while that of TIR and GMI was very strong, thus GMI may better reflect glycaemic control than HbA1c in early pregnancy.
“Each 10% increase in TIR was associated with a 0.3% reduction in HbA1c throughout pregnancy, which was lower than other published studies in nonpregnant populations reporting a 0.5%–0.8% reduction in HbA1c.
“Further studies are needed to understand the relationship between TIR and GMI and how GMI may affect maternal and fetal complications.”