Table 4.

Added value of CSF and blood KLK8 on diagnostic accuracy of CSF AD biomarkers

	AD versus CON				MCI versus CON
	CSF KLK8		Blood KLK8		CSF KLK8		Blood KLK8
	AUC (95% CI)	P value	AUC (95% CI)	P value	AUC (95% CI)	P value	AUC (95% CI)	P value
Aβ42	0.94 (0.87 to 1.0)		0.96 (0.92 to 1.0)		0.88 (0.78 to 0.98)		0.90 (0.82 to 0.98)
Aβ42+KLK8	0.97 (0.94 to 1.0)		0.97 (0.92 to 1.0)		0.99 (0.96 to 1.0)		0.96 (0.92 to 1.0)
AUC difference	0.04 (−0.02 to 0.09)	0.20	0.01 (−0.03 to 0.05)	0.59	0.11 (0.01 to 0.21)	0.03	0.06 (−0.01 to 0.13)	0.06
T-tau	0.94 (0.89 to 0.99)		0.95 (0.91 to 0.99)		0.94 (0.87 to 1.0)		0.95 (0.90 to 1.0)
T-tau +KLK8	0.96 (0.91 to 1.0)		0.97 (0.93 to 1.0)		1.0 (1.0 to 1.0)		1.0 (1.0 to 1.0)
AUC difference	0.02 (−0.02 to 0.05)	0.32	0.01 (−0.01 to 0.04)	0.36	0.06 (−0.01 to 0.13)	0.11	0.05 (−0.01 to 0.1)	0.07
P-tau	0.98 (0.93 to 1.0)		0.97 (0.93 to 1.0)		0.88 (0.72 to 1.0)		0.91 (0.81 to 1.0)
P-tau +KLK8	1.0 (1.0 to 1.0)		0.97 (0.93 to 1.0)		1.0 (1.0 to 1.0)		0.98 (0.95 to 1.0)
AUC difference	0.02 (−0.02 to 0.07)	0.30	−0.003 (−0.02 to 0.01)	0.69	0.12 (−0.04 to 0.28)	0.15	0.07 (−0.03 to 0.18)	0.18
Aβ42+T tau+P-tau	0.97 (0.91 to 1.0)		0.98 (0.96 to 1.0)		0.91 (0.76 to 1.0)		0.92 (0.81 to 1.0)
Aβ42+T tau+P tau+KLK8	1.0 (1.0 to 1.0)		1.0 (1.0 to 1.0)		1.0 (1.0 to 1.0)		1.0 (1.0 to 1.0)
AUC difference	0.03 (−0.03 to 0.09)	0.29	0.02 (−0.01 to 0.04)	0.25	0.09 (−0.06 to 0.24)	0.23	0.08 (−0.02 to 0.19)	0.10

AUCs of CSF AD core biomarkers (ie, CSF Aβ₄₂, CSF T-tau, CSF P-tau each and combination of all three) are compared with AUCs of CSF AD biomarker of interest with added value of CSF or blood KLK8. Data were adjusted for gender, age and study group as well as for biomarker of interest. p values were determined by DeLong test.

Aβ₄₂, β-amyloid 42; AD, Alzheimer’s disease; AUC, area under the curve; CON, controls; CSF, cerebrospinal fluid; MCI, mild cognitive impairment due to AD; P, p value; P-tau, phosphorylated tau; T-tau, total tau.