Performance of a validated spontaneous preterm delivery predictor in South Asian and Sub-Saharan African women: a nested case control study

Figures & data

Table 1. Comparison of AMANHI and U.S. validation cohorts.

	AMANHI (N = 298)	U.S. Validation Cohort [12] (N = 54)	p-value
Maternal age (years)
Mean (SD)	26.1 (5.97)	26.2 (6.25)	.90
Median [Q1, Q3]	25.0 [21.0, 30.0]	24.5 [21.3, 30.0]	.94
Body mass index (kg/m^2)
Mean (SD)*	21.8 (4.19)	27.7 (6.22)	<.001
Median [Q1, Q3]*	20.8 [18.6, 24.0]	26.5 [22.3, 31.3]	<.001
Gravida
Multigravida	235 (78.9%)	41 (75.9%)	.60
Primigravida	63 (21.1%)	13 (24.1%)
Prior PTB^+ (Multigravida)
No	225 (95.7%)	34 (82.9%)	.006
Yes	10 (4.2%)	7 (17.0%)
Gestational age at blood draw (days)
Mean (SD)	128 (6.39)	140 (4.20)	<.001
Median [Q1, Q3]	127 [122, 134]	139 [135, 144]	<.001
Gestational age at birth (days)
Mean (SD)	267 (18.4)	265 (24.2)	.44
Median [Q1, Q3]	271 [256, 281]	273 [256, 281]	.90

*Missing BMI values omitted from calculations: AMANHI cohort, n = 39; U.S. cohort, n = 1.

⁺Prior PTB is restricted to prior sPTB in the U.S. validation cohort. Prior PTB is not limited by the timing of initiation of delivery in the AMANHI cohort.

Table 2. Comparison of three sPTB predictive models containing IBP4/SHBG.

	sPTB < 37					sPTB < 34
Model	AUC	95% CI	p-value	Cases (n)	Controls (n)	AUC	95% CI	p-value	Cases (n)	Controls (n)
U.S. validated predictor: IBP4/SHBG	0.55	0.48–0.62	.069	99	199	0.62	0.49–0.75	.044	19	214
Adjusted for demographic differences: IBP4/SHBG + GABD*BMI	0.64	0.57–0.71	<.001	88	171	0.66	0.51–0.82	.012	17	184
Discovery phase model: IBP4/SHBG + GABD*BMI + (EGLN x PRL) / TETN	0.73	0.66–0.79	<.001	88	171	0.78	0.67–0.90	<.001	17	184

GABD – gestational age at blood draw; GABD*BMI denotes the addition of the main effects of GABD and BMI plus their interaction (product): GABD + BMI + GABD:BMI.

Figure 1. Kaplan-Meier analysis of GA at delivery for lower- and higher-risk groups. Time-to-event analysis shows the rate of births for the top 15% of scores (higher risk) in the discovery phase predictor (IBP4/SHBG + GA at blood draw * BMI + [EGLNxPRL]/TETN) vs. low scores (lower risk). Vertical lines indicate delivery at 34 and 37 weeks.

Saade GR, Boggess KA, Sullivan SA, et al. Development and validation of a spontaneous preterm delivery predictor in asymptomatic women. Am J Obstet Gynecol. 2016;214(5):633.e1–633–e24.

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Data availability statement

Deidentified individual participant data will be made available upon approval of the manuscript, including data dictionaries and data that underlie the results reported in this article. Data will be shared with researchers who contact either of the corresponding authors requesting use of the data for research on preterm birth in LMICs. Requestors will need to sign a data access agreement.