A prospective cohort study on the clinical utility of second trimester mean arterial blood pressure in the prediction of late-onset preeclampsia among Nigerian women
Background: Early detection of preeclampsia will help reduce the morbidities and mortalities associated with the disorder. Late-onset preeclampsia was the predominant presentation in this cohort. The search for biomarkers for predicting preeclampsia is still ongoing. Mean arterial blood pressure (MABP), which has the advantage of presenting a single cutoff value compared with the use of systolic and diastolic blood pressure measurements, merits evaluation.
Aim: The study aims to evaluate the clinical utility of second trimester MABP in the prediction of preeclampsia.
Methods: This was a prospective cohort study of 155 normotensive, nonproteinuric pregnant women without prior history of gestational hypertension. The women were booked patients attending the antenatal clinic at the Lagos University Teaching Hospital and were all in their second trimesters of pregnancy. The outcome measures were systolic blood pressure, diastolic blood pressure, and MABP. The end point of the study was the development of preeclampsia. The diagnosis of preeclampsia was made by the attending obstetrician. The data were analyzed using the IBM SPSS statistical software. Statistical significance was set at P < 0.05.
Results: One hundred and fifty-five pregnant women participated in the study. Eleven (7.1%) of the women developed preeclampsia after 34 weeks gestation and 144 (92.9%) had normal pregnancy. The mean gestational age at the time of assessment was 18.88 ± 3.15 weeks with a range of 14 weeks to 27 completed weeks. There was a statistically significant increase in the systolic blood pressure, diastolic blood pressure, and MABP values in the group of women who later developed preeclampsia, P = 0.005, 0.001, and <0.001, respectively. At a false-positive rate of 10%, MABP value of 88.33 mmHg predicted preeclampsia with a specificity of 90% and a sensitivity of 45.5%, P <0.05. The area under the receiver-operative characteristics curve (AUC) was 0.732 (95% confidence interval, 0.544-0.919, P = 0.011). The negative predictive value (NPV) was 88.88% and the positive predictive value (PPV) was 45.45%, P < 0.05. At an MABP cutoff of 88.33 mmHg, preeclampsia was predicted with a relative risk of 4.44 and a positive likelihood ratio of 6.46, P < 0.05.
Conclusions: With an AUC of 0.732, MABP performed moderately (considering that excellent performance has an AUC of 1.0) in the prediction of late-onset preeclampsia in Nigerian women. Its high NPV suggests a strong ability to rule out preeclampsia and help to appropriate management.
Keywords: Mean arterial blood pressure preeclampsia, systolic blood pressure, diastolic blood pressure, Nigerian women