Estimated impact of introduction of new diagnostic criteria for gestational diabetes mellitus

Table 1 Patient characteristics per group based on classification of oral glucose tolerance test results

	n (%)	Group 1: non-GDM	Group 2: GDM by WHO 1999 only1	P value2	Group 3: GDM by WHO 2013 only	P value2	Group 4: GDM by both criteria1	P value2
n (%)	3338	2119 (63.5)	137 (4.1)		576 (17.2)		506 (15.2)
Age, yr	3336	32.3 (28.5-35.7)	34.1 (30.4-38.0)	< 0.001	33.0 (29.0-36.7)	0.002	33.6 (30.3-37.0)	< 0.001
Age group, n (%)	3336
< 30 yr		698 (33.0)	31 (22.6)	0.002	174 (30.2)	0.031	117 (23.1)	< 0.001
30-35 yr		806 (38.1)	51 (37.2)		204 (35.4)		185 (36.6)
≥ 35 yr		613 (29.0)	55 (40.1)		198 (34.4)		204 (40.3)
Prepregnancy BMI, kg/m2	3156	24.3 (21.8-27.9)	24.7 (22.7-28.7)	0.072	29.0 (24.5-33.6)	< 0.001	28.0 (24.2-32.3)	< 0.001
Prepregnancy BMI group, n (%)	3156
< 30 kg/m2		1669 (83.7)	104 (80.6)	0.598	309 (56.6)	< 0.001	314 (64.5)	< 0.001
≥ 30-< 35 kg/m2		207 (10.4)	18 (14.0)		133 (24.4)		102 (20.9)
≥ 35 kg/m2		118 (5.9)	7 (5.4)		104 (19.0)		71 (14.6)
Ethnicity, n (%)	3248
Caucasian		1126 (54.8)	69 (51.1)	0.402	292 (51.7)	0.378	241 (48.7)	0.030
Mediterranean		616 (30.0)	40 (29.6)		176 (31.2)		166 (33.5)
African, Caribbean		72 (3.5)	3 (2.2)		19 (3.4)		17 (3.4)
Asian		53 (2.6)	7 (5.2)		16 (2.8)		22 (4.4)
Hindustan		37 (1.8)	3 (2.2)		18 (3.2)		15 (3.0)
Other		150 (7.1)	13 (9.5)		44 (7.6)		34 (6.7)
Gravidity	3336	2 (1-3)	2 (1-3)	0.368	2 (2-4)	< 0.001	2 (2-3)	0.045
Parity, n (%)	3323
0		803 (37.9)	46 (33.6)	0.102	171 (29.7)	< 0.001	169 (33.4)	0.010
1		785 (37.0)	48 (35.0)		231 (40.1)		183 (36.2)
≥ 2		519 (24.9)	43 (31.4)		173 (30.0)		152 (30.0)
Smoking during pregnancy, n (%)	3270	277 (13.3)	15 (11.1)	0.470	94 (16.8)	0.031	79 (16.1)	0.104
Conception spontaneous, n (%)	3277	1866 (89.8)	120 (88.9)	0.748	496 (87.9)	0.216	431 (86.4)	0.029
Multiple pregnancy, n (%)	3336	84 (4.0)	9 (6.6)	0.138	10 (1.7)	0.010	33 (6.5)	0.012
Gestational age at OGTT, wk	3336	27.1 (25.1-29.6)	28.1 (25.4-32.7)	0.041	27.0 (24.6-29.1)	< 0.001	27.0 (23.9-29.7)	< 0.001
OGTT fasting plasma glucose value, mmol/L	3336	4.6 (4.4-4.8)	4.7 (4.5-4.8)	0.087	5.2 (5.1-5.4)	< 0.001	5.4 (5.0-5.8)	< 0.001
OGTT 2-h post load glucose value, mmol/L	3298	5.7 (4.9-6.4)	8.0 (7.8-8.2)	< 0.001	6.4 (5.7-6.9)	< 0.001	8.7 (8.1-9.6)	< 0.001

Continuous variables are presented as mean ± SD or median (interquartile range). Percentages may not add up to 100% due to rounding.

¹Women in this group received treatment for gestational diabetes mellitus.

²P value reported compared to group 1: non-gestational diabetes mellitus.

GDM: Gestational diabetes mellitus; BMI: Body mass index; OGTT: Oral glucose tolerance test; WHO: World Health Organization.