Addition of NT-proBNP to sFlt-1/PlGF ratio improves prediction of pre-eclampsia requiring delivery within 1 week, when sFlt-1/PlGF ratio is above 38: results of longitudinal cohort study

Short-term prediction of pre-eclampsia using the sFlt-1/PlGF ratio is characterized by frequent false positive results. As such, no treatment can be recommended to test positive patients. Multiple measurements are common in these patients. To evaluate the influence of NT-proBNP, uric acid and the sFlt-1/PlGF ratio in the prediction of delivery with pre-eclampsia within one week in singleton pregnancies from 24 weeks 0 days to 36 weeks 6 days of gestation, with signs and symptoms of pre-eclampsia and a sFlt-1/PlGF ratio above 38. A longitudinal prospective cohort of singleton pregnancies, with clinically suspected pre-eclampsia, enrolled between January 2015 and June 2017. Multiple samples per patient were allowed, but restricted to one sample per gestational week. From 495 enrolled patients, 270 blood samples from 134 patients were ultimately analysed. By using generalized estimating equations (GEE), the best fit model was selected for prediction of delivery with pre-eclampsia within one week. The model included the sFlt-1/PlGF ratio, NT-proBNP and the gestational week at the time of the measurement. This combined model was compared with the GEE model based on the sFlt-1/PlGF ratio and the gestational week at the time of the measurement (reduced model), using area under the curve (AUC) of paired ROC curves. The AUC of the combined model was 0.845 (95% CI: 0.787-0.896), which was significantly greater (p=0.011) than of the reduced model 0.786 (95% CI: 0.722-0.844). The addition of NT-proBNP improves the short-term prediction of delivery due to pre-eclampsia compared to the sFlt-1/PlGF ratio alone, when above 38. This finding should be considered in future research on the assessment of short-term risk of delivery due to pre-eclampsia.