Clinical significance of self-reported cough intensity and frequency in patients with interstitial lung disease: a cross-sectional study

Table 2 Unadjusted analysis of factors associated with cough intensity in patients with interstitial lung disease

Variable	IIPs (n = 70)		CTD-ILD (n = 49)		CHP (n = 10)		Combined
Variable	ρ	p-value	ρ	p-value	ρ	p-value	ρ	p-value
Age, years	−0.065	0.595	0.063	0.669	0.339	0.337	−0.003	0.973
Male sex	–	0.644	–	0.658	–	0.833	–	0.737
Current smoker	–	0.598	–	0.490	–	–	–	0.156
Pack-years of smoking	−0.128	0.293	−0.144	0.323	−0.174	0.630	−0.031	0.728
Body mass index^a	−0.297	0.013	−0.133	0.362	−0.025	0.949	−0.166	0.061
FSSG score	0.146	0.229	0.342	0.016	0.366	0.298	0.207	0.019
MRC chronic dyspnoea scale^b	0.154	0.208	0.325	0.023	0.007	0.986	0.208	0.018
Pulmonary function tests, % predicted^c
FEV₁	−0.118	0.344	0.021	0.887	0.097	0.805	−0.091	0.316
FVC	−0.206	0.097	−0.068	0.647	0.084	0.831	−0.123	0.175
TLC	−0.212	0.088	−0.011	0.943	−0.109	0.781	−0.186	0.040
D_LCO	−0.316	0.010	−0.223	0.128	−0.310	0.417	−0.311	< 0.001
Composite Physiologic Index^c	0.370	0.002	0.209	0.154	0.142	0.715	0.295	0.001
Medication
Glucocorticoid	–	0.986	–	0.681	–	0.114	–	0.168
Antifibrotic agent	–	0.590	–	–	–	0.431	–	0.114
Proton pump inhibitor	–	0.156	–	0.074	–	0.830	–	0.057

The Spearman rank correlation was used to assess correlations between the data. The p-values for binary variables were determined using the Mann-Whitney U test. CHP, chronic hypersensitivity pneumonia; CTD-ILD, connective tissue disease-associated interstitial lung disease; D_Lco, diffusing capacity of the lung for carbon monoxide; FEV₁, forced expiratory volume in 1 s; FSSG, frequency scale for the symptoms of gastro-oesophageal reflux disease; FVC, forced vital capacity; IIPs, idiopathic interstitial pneumonias; MRC, Medical Research Council; TLC, total lung capacity. ^aIIPs (n = 70), CTD-ILD (n = 49), CHP (n = 9); ^bIIPs (n = 69), CTD-ILD (n = 49), CHP (n = 10); ^cIIPs (n = 66), CTD-ILD (n = 48), CHP (n = 9)

ISSN: 1471-2466