A Nested Case-Control Study of the Relationship between Salivary Inflammatory Mediators, Periodontal Parameters, and Preterm Birth in a Chinese Population

Table 6

ROC curve of alone and combined detection of BI and saliva-PGE2 levels.

Variables	Cut off point	AUC	Sensitivity	Specificity
BI	1.66	0.82	90.0	62.5
PGE2 (pg/ml)	117.70	0.78	90.0	60.0
BI+PGE2 (pg/ml)	BI: 1.25; PGE2: 109.75	0.91	90.0	87.5

BI: bleeding index; PGE2: prostaglandin E2; AUC: the area under ROC; sensitivity and specificity were percentages.