Small airway dysfunction in patients with cough variant asthma: a retrospective cohort study

BMC Pulmonary Medicine

Table 3 Results of ROC analysis of PD₂₀ and spirometry

Parameter	PD₂₀ (mcg)	Sputum eosinophils%	MMEF% predicted	FEF_50% predicted	FEF_75% predicted
CVA versus CA
AUC (95% CI)	0.582	0.575	0.615	0.621	0.606
Cut-off	0.17	4.7	47.85%	47.95%	38.2%
Sensitivity/specificity (%)	73.8/41.4	65.7/52.1	63.9/54.9	73.4/48.6	75.7/43.1
p-value	0.001	0.005	< 0.001	< 0.001	< 0.001
95% confidence interval
Upper limit value	0.627	0.628	0.659	0.665	0.649
Lower limit value	0.537	0.523	0.570	0.577	0.560

CVA, cough variant asthma; CA, classic asthma; PD₂₀, Does of methacholine induce a 20% decrease in FEV₁. Significant p value < 0.05.

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