Table 2.

Prediction properties of internal and external validation.

Method	Internal validation						External validation
	AUC	Cutoff	SEN	SPE	PPV	NPV	SEN	SPE	PPV	NPV
Decision Tree*	/	/	0.980	0.554	0.941	0.791	0.910	0.405	0.784	0.653
Random Forest*	/	/	0.974	0.605	0.947	0.760	0.917	0.446	0.798	0.692
DB	0.567	93.7	0.837	0.318	0.900	0.212	0.646	0.537	0.769	0.389
		76.9	0.950	0.146	0.890	0.286	0.878	0.372	0.769	0.563
ln(ALP)	0.572	6.3	0.656	0.468	0.900	0.157	0.514	0.545	0.729	0.320
		7.0	0.950	0.121	0.887	0.249	0.997	0	0.703	0
ln(GGT)	0.845	5.8	0.786	0.796	0.966	0.338	0.885	0.124	0.706	0.313
		4.9	0.950	0.408	0.921	0.528	0.997	0	0.703	0
GGT < 300 (U/l)			0.000	1.000	/	0.344	0.000	1.000	/	0.508
GGT≥300 (U/l)			0.960	0.200	0.965	0.178	0.945	0.033	0.867	0.083
Logistic Regression*§	0.898	0.85	0.857	0.803	0.969	0.434	0.712	0.760	0.876	0.526
		0.65	0.950	0.599	0.945	0.622	0.837	0.570	0.823	0.595
GGT < 300 (U/l)			0.448	0.957	0.952	0.477	0.284	0.890	0.714	0.563
GGT≥300 (U/l)			0.951	0.350	0.971	0.237	0.900	0.367	0.905	0.355

Abbreviations: AUC, area under receiver operating characteristic (ROC) curve; SEN, sensitivity; SPE, specificity; PPV, positive prediction value; NPV, negative prediction value.

Note: *Based on the combination of gender, weight, DB, ln(ALP) and ln(GGT).^§The external validation was based on the cutoff value.