Biomarker selection for medical diagnosis using the partial area under the ROC curve

BMC Research Notes

Table 8 The Forward and Backward selections in DMD and heart disease examples

I. Forward selection
Example	Step	Marker enters	Test statistic	Test value	p-value	Marker selected
DMD	1	X ₁	$\hat{pAUC}$	0.0882	0.000^*	X ₁
	2	X ₃	${\hat{a}}_{3}$	0.1775	0.006^*	X ₁ ,X ₃
	3	X ₂	${\hat{a}}_{2}$	0.0653	0.272	X ₁ ,X ₃
Heart Disease	1	lutein	$\hat{pAUC}$	0.0099	0.012^*	lutein
	2	TBARS	${\hat{a}}_{T BARS}$	0.7922	0.082	lutein
	3	uric acid	${\hat{a}}_{uric acid}$	0.5091	0.258	lutein
	4	HDL Chol	${\hat{a}}_{HDL C}$	0.3352	0.428	lutein
II. Backward selection
Example	Step	Marker enters	Test statistic	Test value	p-value	Marker selected
DMD	1	All	$\hat{pAUC}$	0.0888	0.000^*	X ₁ ,X ₂ ,X ₃
	2	X ₂	${\hat{a}}_{2}$	0.0653	0.272	X ₁ ,X ₃
	3	X ₃	${\hat{a}}_{3}$	0.1775	0.006^*	X ₁ ,X ₃
	4	X ₁	${\hat{a}}_{1}$	0.9841	0.000^*	X ₁ ,X ₃
Heart Disease	1	All	$\hat{pAUC}$	0.0165	0.002^*	lutein,TBARS, HDL Chol, uric acid
	2	HDL Chol	${\hat{a}}_{HDL C}$	0.0834	0.632	lutein, TBARS, uric acid
	3	uric acid	${\hat{a}}_{uricacid}$	0.1916	0.316	lutein, TBARS
	4	TBARS	${\hat{a}}_{T BARS}$	0.7922	0.100	lutein

ISSN: 1756-0500