Table 3. Results of a multivariate analysis of bronchial and nasal NO concentrations, incorporating FEV1, CRP, pathogen colonisation, and antibiotic therapy into a multiple linear regression model: regression coefficients, significance levels, and confidence intervals.

Dependent variable	Explanatory variable	Regression coefficient β	p-value	95% confidence interval
log10 NO bronchial	Constant	1.109	0.000	0.828	1.391
	bronchial colonisation with P.a.	0.015	0.848	−0.137	0.167
	bronchial colonisation with S.a.	−0.083	0.291	−0.241	0.074
	no bronchial colonisation	0
	antibiotic therapy+Azithromycin	−0.025	0.778	−0.199	0.150
	antibiotic therapy	0.184	0.034	0.015	0.352
	no antibiotics	0
	FEV1 (% predicted)	0.001	0.573	−0.002	0.003
	CRP (mg/l)	−0.003	0.443	−0.012	0.005
log10 NO nasal	Constant	2.576	0.000	2.106	3.046
	bronchial colonisation with P.a.	0.013	0.927	−0.266	0.292
	bronchial colonisation with S.a.	0.238	0.112	−0.058	0.534
	no bronchial colonisation	0
	antibiotic therapy+Azithromycin	0.44	0.790	−0.285	0.373
	antibiotic therapy	0.92	0.451	−0.151	0.335
	no antibiotics	0
	FEV1 (% predicted)	0.002	0.364	−0.002	0.006
	CRP (mg/l)	−0.015	0.053	−0.031	0.000

Abbreviations: P.a. – Pseudomonas aeruginosa; S.a. – Staphylococcus aureus; FEV 1– forced expiratory volume in one second; CRP – C-reactive protein.