Utility of oral glucose tolerance test in predicting type 2 diabetes following gestational diabetes: Towards personalized care

Table 1 Demographic characteristics of Emirati women who delivered in 2007 in Latifa Women and Children Hospital and Dubai Hospital, and were successfully followed up in 2016¹

	mean ± SD
Number (n)	1231
Age (yr)	38.7 ± 6.1
BMI (kg/m2)	31.1 ± 6.7
Parity (n)	5.74 ± 3.3
Live born (n)	4.53 ± 3.0
Still birth (n)	0.1 ± 0.3
Miscarriage (n)	1.1 ± 1.7

¹Data were obtained in 2016.

BMI: Body mass index.

Table 2 Results of oral glucose tolerance test of 1231 Emirati pregnant women performed during their 24-28 wk of pregnancy in 2007, n (%)

Positive Diagnostic criteria1	Normal	GDM	T2D
Isolated FBG	995 (80.8)	215 (17.5)	21 (1.7)
Isolated 2hrBG	1121 (91.0)	95 (7.7)	15 (1.2)
Associated FBG and 2hrGB	1179 (95.8)	52 (4.2)	0 (0)
Total	833 (67.7)	362 (29.4)	36 (2.9)

¹International Association of Diabetes and Pregnancy Study Groups (IADPSG)[5] criteria.

OGTT: Oral glucose tolerance test; GDM: Gestational diabetes mellitus; T2D: Type 2 diabetes; FBG: Fasting blood glucose; 2hrBG: 2-h blood glucose.

Table 3 Glycemic status of 1231 Emirati pregnant women, who were tested previously in 2007, and underwent post-natal glycemic tests in 2016

Diagnostic criteria1	Total number tested	Normal	Impaired FBG	IGT	Impaired FBG and IGT	T2D
FBG	872	542	203	-	-	127
Post-prandial 2hrBG	118	86	-	28	-	4
OGTT	241	146	23	52	10	10
Total	1231	774	226	80	10	141

¹American Diabetes Association criteria for diagnosis of diabetes mellitus[8].

FBG: Fasting blood glucose; IGT: Impaired glucose tolerance; T2D: Type 2 diabetes; 2hrBG: 2-h blood glucose; OGTT: Oral glucose tolerance test.

Table 4 Cross-tabulation of the glycemic status of Emirati women (n = 1231) who delivered in 2007, against their glycemic status in 2016, n (%)

IADPSG diagnostic criteria for GDM (2007)	ADA diagnostic criteria (2016)
	Fasting				2 h
	Total	Normal	IFG	T2D	Total	Normal	IGT	T2D
Fasting
Normal	262 (100)	205 (78)	43 (16)	14 (5)	89 (100)	54 (61)	30 (34)	5 (5)
GDM	267 (100)	113 (42)	89 (33)	65 (25)	44 (100)	31 (70)	9 (21)	4 (9)
T2D	26 (100)	2 (8)	3 (11)	21 (81)	2 (100)	1 (50)	1 (50)	0 (0)
Total	555 (100)	320 (58)	135 (24)	100 (18)	135 (18)	86 (64)	40 (29)	9 (7)
2Hr
Normal	670 (100)	495 (74)	138 (21)	37 (5)	252 (100)	197 (78)	51 (20)	4 (2)
GDM	147 (100)	68 (46)	53 (36)	26 (18)	34 (100)	13 (38)	20 (59)	1 (3)
T2D	26 (100)	7 (27)	5 (19)	14 (54)	4 (100)	1 (25)	2 (50)	1 (25)
Total	843 (100)	843 (68)	196 (23)	77 (9)	290 (100)	211 (73)	73 (25)	6 (2)

GDM: Gestational diabetes mellitus; T2D: Type 2 diabetes; IFG: Impaired fasting glucose; IGT: Impaired glucose tolerance; FBG: Fasting blood glucose; 2hrBG: 2-h blood glucose.

Table 5 Sensitivity and specificity of fasting blood glucose and 2-h blood glucose in predicting type 2 diabetes following gestational diabetes mellitus in Emirati women¹

IADPSG diagnostic criteria for GDM (2007)	ADA diagnostic criteria for T2D (2016)
	FBG		2hrBG
	T2D (n)	Normal (n)	T2D (n)	Normal (n)
GDM	65	202	1	33
Normal	14	248	4	248
Point estimates and 95%CIs
True prevalence	0.149 (0.12, 0.183)		0.017 (0.006, 0.04)
Sensitivity	0.823 (0.721, 0.9)		0.200 (0.005 0.716)
Specificity	0.551 (0.504, 0.598)		0.883 (0.839, 0.918)
Positive predictive value	0.243 (0.193, 0.299)		0.029 (0.001, 0.153)
Negative predictive value	0.947 (0.912, 0.97)		0.984 (0.96, 0.996)
Positive likelihood ratio	1.833 (1.586, 2.118)		1.703 (0.287, 10.12)
Negative likelihood ratio	0.322 (0.198, 0.521)		0.906 (0.584, 1.408)
Odds ratio	5.7 (3.108, 10.455)		1.879 (0.204, 17.32)

¹The R 4.02 statistical software was used to plot the receiver operating characteristic curve.

GDM: Gestational diabetes mellitus; T2D: Type 2 diabetes; FBG: Fasting blood glucose; 2hrBG: 2-h blood glucose.