Table 1.
Description of Study Population.
Figure 1.
Biomarkers of Occult Placental Malaria Infection.
(A-C) Box plots showing the median (IQR) of peripheral blood biomarkers (whiskers denote the 5-95% percentiles and outliers are plotted as dots), with the associated (D-F) receiver operating characteristic (ROC) curves and (G-I) decision plots of sensitivity and specificity generated from the ROC curves. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curves and determining the area under the ROC curve (AUC). The AUC were compared and all three biomarkers had comparable diagnostic performance (method of Delong et al.). The dotted lines represent the cut-point for dichotomizing the biomarkers, as defined using the Youden index.
Table 2.
Peripheral Plasma Biomarkers in Occult Placental Malaria Infections.
Figure 2.
Combinations of Biomarkers and Clinical Parameters Improve Diagnostic Accuracy.
(A–C) We generated a simple scoring system based on the summation of dichotomous variables that were significantly associated with the presence of smear positive parasites in the placenta, but not the periphery. (A) The clinical score (0–2) consisted of maternal anemia (1) and non-specific febrile symptoms (any one of: fever, chills, headache = 1). (B) The biomarker score (0–3) consisted of high CRP levels (>30.5 mg/mL = 1), low leptin levels (<8.8 ng/mL = 1), and low sFlt-1 levels (<16.9 ng/mL = 1). (C) The clinical score and biomarker score were integrated to generate the final score (0–5). (D) The diagnostic ability of the different scoring systems was assessed using ROC curve analysis. The clinical + biomarker score had an AUC of 0.85 (95% CI, 0.81-0.89) and was significantly better than the clinical score at discriminating between women with occult PM infections compared to smear-negative controls, p = 0.001 (method of Delong, et al.).