Table 3

Simple logistic regression analysis assessing the effect of a high dose of ICS and atopy on the FeNO threshold for identifying sputum eosinophilia ≥3%

Characteristics		FeNO cut-off (ppb)	Specificity (%)	Sensitivity (%)	PPV (%)	NPV (%)	p-Value
High-dose ICS	Yes	27	62	76	59	78	0.028
High-dose ICS	No	48	84	56	72	72	0.028
Atopy	Yes	49	84	56	72	72	0.049
Atopy	No	30	64	74	60	77	0.049
Smoking	Yes	28	62	76	59	78	0.066
Smoking	No	46	82	58	70	73	0.066
Male	Yes	37	71	66	63	74	0.236
Male	No	48	84	56	72	72	0.236
Age	≥40	43	80	62	69	74	0.873
Age	<40	42	79	64	69	75	0.873

Age and sex did not contribute significantly to the predictive value of FeNO (for more details on calculation see online supplement).
FeNO, exhaled nitric oxide; ICS, inhaled corticosteroids. NPV, negative predictive value; PPV, positive predictive value