Discriminatory Accuracy of Preeclampsia Risk Factors in Primary Care

Abstract

Although it is common to use risk factors in the screening for preeclampsia, they do not always accurately identify patients who truly have this condition. To determine the discriminatory accuracy of known preeclampsia risk factors, both individually and in combination. We studied patients undergoing prenatal care who were diagnosed with preeclampsia or eclampsia (n=160 cases) in primary care and those who were not (n=430 controls). Data on history of preeclampsia, type 2 diabetes, chronic hypertension, multiple gestation, first pregnancy, pregnancy interval ≥10years, overweight/obesity, mean arterial pressure (MAP) ≥80mmHg, and age (<20years and ≥40years) were obtained using a dichotomous scale. Discriminatory accuracy indicators were true-positive (TP) and false-positive (FP) rates, positive and negative likelihood ratios (LR+ and LR-), diagnostic odds ratio (DOR), and the area under the receiver-operating characteristic (AUROC) curve; stratified by parity. The case-control status was the reference standard. Certain combinations performed better than individual factors, independent of parity status. Among multiparous women, MAP ≥80mmHg together with previous preeclampsia and overweight/obesity accumulated the greatest number of discriminatory accuracy indicators, with acceptable values: TP, 72.2%; FP, 1.5%; LR+, 48.4; LR-, 0.3; DOR, 171.6; and AUROC, 0.85. Discriminatory accuracy was low for almost all individual preeclampsia risk factors. However, the accuracy improved after some factors were combined. To the best of our knowledge, this is the first study to examine the discriminatory accuracy of preeclampsia risk factors used for screening high-risk pregnancies in primary care in Mexico.