Performance of flash continuous glucose monitoring and glycemic marker correlations in Chinese pregnant women with non-type 1 diabetes

Table 1 Characteristics of participants.

Characteristic	GDM	T2DM	P value
N	89 (58.6%)	63 (41.4%)	-
Age (years)	35.3 ± 3.8	35.6 ± 3.9	0.717
Age at diagnosis (years)	35 (33-38)	33 (29.5-36)	0.002
Gestational age at first visit (weeks)	29.3 (26.6-32.7)	10.7 (8.1-16.7)	< 0.001
Pre-pregnancy BMI (kg/m2)	23.3 (20.4-25.8)	25.1 (22.1-29.0)	0.003
Gravidity	2 (1-3)	1 (1-2)	0.04
Parity	0 (0-1)	0 (0-0)	0.072
Mode of conception
Natural conception	68 (76.4%)	53 (84.1%)	0.495
IVF-ET	16 (18.0%)	8 (12.7%)	0.488
Ovulation induction by letrozole	5 (5.6%)	2 (3.2%)	0.516
Singleton pregnancy	83 (93.3%)	62 (98.4%)	0.24
Multiple pregnancy	6 (6.7%)	1 (1.6%)	0.24
HbA1c (%)	5.2 (5.0-5.5)	5.3 (5.0-5.9)	0.02
GA (%)	13.3 (12.2-13.7)	13.3 (12.6-14.6)	0.364
Hemoglobin (g/L)	125.7 ± 10.1	124.9 ± 10.8	0.613
Serum iron (μg/dL)	92.0 (75.5-116.0)	108.0 (82-132)	0.049
Serum ferritin (ng/mL)	28.5 (16.0-52.8)	53 (35-92)	< 0.001
Serum vitamin B12 (pg/mL)	312 (228-433)	342 (281-476)	0.072
Pharmacotherapy
Insulin	50 (56.2%)	40 (63.5%)	0.012
Metformin	0 (0%)	1 (1.6%)	0.349
Insulin and metformin	0 (0%)	8 (12.7%)	< 0.001
CGM profiles	2 (1-3)	2 (1-6)	0.063
CGM metrics
Number of days CGM worn (days)1	12.5 (11.3-12.8)	12.9 (11.3-12.9)	0.081
Percentage of time CGM is active (%)	100 (100-100)	100 (100-100)	0.636
Mean glucose (mmol/L)	5.5 (5.2-5.8)	5.4 (5.0-5.9)	0.214
Time in range (%) (3.5-7.8 mmol/L)	93.4 (87.5-96.8)	91.1 (84.7-95.4)	0.001
Time above range (%) (> 7.8 mmol/L)	3.9 (1.3-8.6)	4.8 (1.6-10.7)	0.045
Time below range (%) (< 3.5 mmol/L)	0.7 (0.2-3.1)	1.4 (0.2-4.3)	0.021
Time below range (%) (< 3.0 mmol/L)	0.1 (0-0.9)	0.2 (0-1.1)	0.215
Coefficient of variation (%)	19.9 (17.5-23.1)	21.9 (19.0-25.5)	< 0.001

¹The first 24 hours of data were excluded from analysis.

Continuous variables with normal distribution are expressed as the mean ± SD, non-normally distributed variables as the median (range), and categorical variables as the number (percentage). A P value below 0.05 indicated statistical significance. GDM: Gestational diabetes mellitus; T2DM: Type 2 diabetes mellitus; BMI: Body mass index; IVF-ET: In vitro fertilization and embryo transfer; HbA1c: Hemoglobin A1c; GA: Glycated albumin; CGM: Continuous glucose monitoring.

Table 2 Mixed-effects models predicting the relationship between mean glucose and hemoglobin A1c in pregnant participants with gestational diabetes mellitus and type 2 diabetes mellitus.

Model	AIC	Fixed effects	Intercept (95%CI)	P value	HbA1c	P value	Other covariates	P value
1	1019.85	Intercept only	5.548 (5.412-5.683)	< 0.001	-	-	-	-
2	901.65	HbA1c	1.957 (1.345-2.569)	< 0.001	0.669 (0.557-0.782)	< 0.001	-	-
3	895.41	HbA1c	1.619 (0.962-2.277)	< 0.001	0.685 (0.573-0.798)	< 0.001	-	-
		Gestational age1					0.010 (0.003-0.017)	0.004
4	899.29	HbA1c	1.529 (0.800-2.259)	< 0.001	0.639 (0.524-0.754)	< 0.001	-	-
		Prepregnancy BMI					0.024 (0.002-0.047)	0.036
5	689.21	HbA1c	1.956 (1.094-2.818)	< 0.001	0.715 (0.597-0.834)	< 0.001	-	-
		Hemoglobin					-0.002 (-0.007 to 0.004)	0.492
6	889.26	HbA1c	2.093 (1.417-2.770)	< 0.001	0.665 (0.552-0.778)	< 0.001	-	-
		Serum iron					-0.001 (-0.003 to 0.001)	0.349
7	676.89	HbA1c	1.165 (0.095-2.235)	0.033	0.692 (0.568-0.816)	< 0.001	-	-
		Gestational age					0.010 (0.002-0.017)	0.010
		Prepregnancy BMI					0.029 (0.005-0.054)	0.018
		Hemoglobin					-0.002 (-0.008 to 0.003)	0.371
		Serum iron					0.000 (-0.002 to 0.003)	0.876

¹Gestational age: Gestational week at the point of data collection.

CI: Confidence intervals; HbA1c: Hemoglobin A1c; AIC: Akaike information criterion; BMI: Body mass index.

Table 3 Mixed-effects models predicting the relationship between mean glucose and glycated albumin in pregnant participants with gestational diabetes mellitus and type 2 diabetes mellitus.

Model	AIC	Fixed effects	Intercept (95%CI)	P value	GA	P value	Other covariates	P value
1	1019.85	Intercept only	5.548 (5.412-5.683)	< 0.001	-	-	-	-
2	937.08	GA	2.518 (1.853-3.184)	< 0.001	0.234 (0.183-0.284)	< 0.001	-	-
3	933.63	GA	2.273 (1.579-2.968)	< 0.001	0.237 (0.187-0.288)	< 0.001	-	-
		Gestational age1					0.008 (0.001-0.015)	0.019
4	908.75	GA	0.523 (-0.393 to 1.438)	0.263	0.253 (0.205-0.302)	< 0.001	-	-
		Prepregnancy BMI					0.072 (0.047-0.096)	< 0.001
5	747.13	GA	2.169 (1.143-3.195)	< 0.001	0.232 (0.174-0.289)	< 0.001	-	-
		Hemoglobin					0.003 (-0.002 to 0.009)	0.269
6	914.80	GA	2.777 (2.076-3.478)	< 0.001	0.242 (0.191-0.293)	< 0.001	-	-
		Serum iron					-0.003 (-0.006 to -0.001)	0.015
7	701.73	GA	0.160 (-1.441 to 1.212)	0.807	0.270 (0.215-0.325)	< 0.001	-	-
		Gestational age					0.010 (0.001-0.016)	0.021
		Prepregnancy BMI					0.076 (0.050-0.102)	< 0.001
		Hemoglobin					0.002 (-0.003 to 0.008)	0.373
		Serum iron					-0.001 (-0.004 to 0.001)	0.242

¹Gestational age: Gestational week at the point of data collection.

CI: Confidence intervals; GA: Glycated albumin; AIC: Akaike information criterion; BMI: Body mass index.