Development and validation of a model that includes two ultrasound parameters and the plasma D-dimer level for predicting malignancy in adnexal masses: an observational study

Table 5 Model development: stepwise regression with backward selection and the Akaike and Bayes information criteria (AIC/BIC)

Steps	Model includes											AIC	BIC
Steps	age	multilocular	SA	BL	ascites	metastases	MS	CA125	CS	PLT	DD	AIC	BIC
0 - starting model	+	+	+	+	+	+	+	+	+	+	+	107.6212	149.8325
1 - “age” removed	–	+	+	+	+	+	+	+	+	+	+	105.8472	144.8115
2 - “metastases” removed	–	+	+	+	+	–	+	+	+	+	+	104.7247	140.4419
3 - “ascites” removed	–	+	+	+	–	–	+	+	+	+	+	103.1334	135.6037
4 - “mulilocular” removed	–	–	+	+	–	–	+	+	+	+	+	102.1436	131.3668
5 - “PLT” removed	–	–	+	+	–	–	+	+	+	–	+	101.5771	127.5533
6 - “MS” removed	–	–	+	+	–	–	–	+	+	–	+	102.1847	121.6669
7 - “CA125” removed	–	–	+	+	–	–	–	–	+	–	+	–	120.4145
8 - “BL” removed	–	–	+	–	–	–	–	–	+	–	+	–	119.9821
model: SA + CS	–	–	+	–	–	–	–	–	+	–	–	–	167.4295
model: SA + DD	–	–	+	–	–	–	–	–	–	–	+	–	121.9826
model: CS + DD	–	–	–	–	–	–	–	–	+	–	+	–	148.0912

(+), included, (−) excluded, BL bilateral lesions, CS color score, DD D-dimer, MS menopausal status, PLT platelet count, SA solid areas

ISSN: 1471-2407