Table 7. Sensitivity and specificity for ASAS-R-CHI with ESCA as a criterion (n = 1152).

cut-off points	Sensitivity (%)	Specificity (%)	Youden's index	PPV (%)	NPV (%)
47.5	100	12.5	0.125	77.42	100
48.5	98.6	15	0.136	77.68	78.13
49.5	98.6	21.2	0.198	78.96	85.71
50.5	97.2	25.2	0.224	79.59	75.00
51.5	97.2	32.8	0.300	81.27	79.61
52.5	93.3	42.1	0.354	82.86	67.68
53.5	93.3	51.1	0.444	85.13	68.53
54.5	91.2	57.5	0.487	86.55	68.53
55.5	87.3	63.3	0.506	87.71	62.43
56.5	77.7	71.6	0.493	89.74	51.70
57.5	69.3	79.2	0.485	90.91	46.23
58.5	59.0	87.1	0.461	89.52	37.21
59.5	49.8	91.4	0.412	94.56	37.77
60.5	37.5	94	0.315	94.94	33.39
61.5	28.3	96.2	0.245	94.95	30.61
62.5	18.7	97.7	0.164	96.06	28.60
63.5	12.0	98.2	0.102	95.24	27.11
64.5	4.6	99.3	0.039	99.50	25.76
65.5	2.1	99.4	0.015	91.30	25.29
66.5	1.1	99.8	0.009	94.29	50.23
68.5	1.1	100	0.011	100	75.21

ASAS-R-CHI: the Chinese version of the revised form of the Appraisal of Self-care Agency Scale. ESCA: the Exercise of Self-care Agency scale