Diagnostic Value of Fractional Exhaled Nitric Oxide and Small Airway Function in Differentiating Cough-Variant Asthma from Typical Asthma

Table 4

Optimal cut-off values for the prediction of CVA.

Parameter	AUC (95% CI)		Cut-off	Sensitivity (%)	Specificity (%)
FeNO	0.660 (0.585–0.735)	<0.001	48.50	90.4	42.2
MMEF75%/25%	0.895 (0.850–0.939)	<0.001	60.02	78.8	87.3
FEF50%	0.873 (0.825–0.921)	<0.001	63.46	80.8	82.4
FEF25%	0.898 (0.854–0.942)	<0.001	45.26	84.6	85.3
Fres	0.695 (0.623–0.767)	<0.001	16.63	81.7	53.9
R5-R20	0.650 (0.575–0.725)	<0.001	0.38	74.0	54.9
X5	0.645 (0.570–0.720)	<0.001	−1.32	74.0	49.0
Combine1	0.912 (0.873–0.952)	<0.001	—	83.7	87.3
Combine2	0.893 (0.849–0.936)	<0.001	—	86.5	83.4
Combine3	0.914 (0.875–0.953)	<0.001	—	84.7	90.2
Combine4	0.742 (0.673–0.810)	<0.001	—	77.0	65.8
Combine5	0.707 (0.637–0.777)	<0.001	—	71.2	61.8
Combine6	0.711 (0.640–0.782)	<0.001	—	80.8	57.9

Combine 1: FeNO + MMEF_75%/25%; Combine 2: FeNO + FEF_50%; Combine 3: FeNO + FEF_25%; Combine 4: FeNO + Fres; Combine 5: FeNO + R5-R20; Combine 6: FeNO + X5. , , , compared with FeNO; #; ##, compared with FEF_25%; $, compared with Fres; and , compared with R5-R20; ^aa, compared with X5.