The prognostic utility of soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PIGF) biomarkers for predicting preeclampsia: a secondary analysis of data from the INSPIRE trial

Table 3 Performance measures of biomarkers in identifying preeclampsia

Model	Regression model output		Model performance corrected for optimism
Model	Coefficient	Intercept	Calibration slope	CITL	C-index	R²	BIC	AUC
Model 1: sFlt-1 only^a	7.37	-29.92	0.98	0	0.94	0.55	144	0.94
Model 2: PIGF only^a	-4.77	8.08	0.99	0	0.87	0.38	184	0.89
Model 3: sFlt-1/PIGF ratio^a	-9.47	4.19	0.99	0	0.94	0.57	139	0.94
Model 4: sFlt-1/PIGF cut-off at 38^b	4.37	-5.81	0.84	0	0.88	0.46	165	0.89

sFlt-1 Soluble fms-like tyrosine kinase – 1, PIGF Placental growth factor, CITL Calibration-in-the-large, BIC Bayesian information criteria (the lowest BIC values indicating better model performance), C-index Concordance index, AUC Area under the curve
^aPredictor variables are continuous values included in the model equation of biomarker/s as every unit increases in log-scale. All model results are optimism corrected and adjusted for the trial arm
^bNo log transformation applied for the cut off predictor variable

ISSN: 1471-2393