Smoking cessation and bronchial epithelial remodelling in COPD: a cross-sectional study

Respiratory Research

Table 2 Bronchial epithelial features of smokers and ex-smokers with COPD

	COPD Smokers	COPD Ex-smokers			p-value §
		combined group	quit < 3.5 years	quit ≥3.5 years
SCM (% of epithelium)	0 (0–27.5)	0 (0-0)*	0 (0–10.4)	0 (0-0)	0.076
SCM (% of patients)	45.7	22.5*	26.3	19.0*	0.049
PAS/AB⁺ area (%)	14.4 (5.2–20.7)	8.1 (3.7–17.2)†	13.5 (6.6–19.6)	7.9 (2.2–16.2)*‡	0.011
Ki-67⁺ cells (/mm BSM)	18.6 (5.3–38.8)	6.2 (1.5–15.6)*	6.9 (4.4–27.6)	2.8 (0.23–13.1)*	<0.001
EGFR⁺ area (%)	11.4 (3.2–17.6)	8.2 (3.2–20.4)	6.7 (2.4–20.4)	8.6 (3.9–21.5)	0.95
Intensity EGFR⁺ area (grey value)	697 (175–1182)	513 (203–1479)	372 (125–1479)	517 (215–1424)	0.95

Data represent median (IQR: 25^th – 75^th percentile). PAS/AB = Periodic acid-Schiff/Alcian blue, SCM = squamous cell metaplasia, EGFR = Epidermal growth factor receptor.
* p < 0.05: compared to COPD smokers, † p < 0.05: compared to COPD smokers adjusted for differences in squamous cell metaplasia (linear regression), ‡ p < 0.05: compared to COPD ex-smokers who quit <3.5 yrs, §p-value from Kruskal-Wallis test between current smokers, < and ≥3.5 yrs ex-smokers with COPD.

ISSN: 1465-993X