Differences in median sRAGE between COPD patients (n = 200) and control subjects (no airflow obstruction and no emphysema, n = 201) taken as the referent category. COPD patients are categorized as a function of the presence and severity of emphysema on computed tomography (CT). Grey bars: unadjusted difference. Black bars: difference adjusted for airflow obstruction, pack-years of smoking, coronary artery disease, diabetes, and dyslipidemia. * p < 0.05, ** p < 0.01, *** p < 0.001 against the referent category.