Fig. 3
From: Dysregulation of the endothelial nitric oxide pathway is associated with airway inflammation in COPD
Serum nitrate and nitrite concentration in smoking controls and patients with COPD. Logarithmically transformed serum nitrate and nitrite concentrations were analysed among smoking control and patients with stable and exacerbated COPD (a and c; ANOVA with post-hoc analysis, ***p < 0.001) and between the onset and the recovery of an acute severe exacerbation (b and d; paired t-test). Control: smoking control subjects, S-COPD: stable COPD, E-COPD: exacerbation of COPD. Data were analysed after log transformation and are shown as geometric mean and geometric standard deviation