Adenocarcinoma was significantly more common in lung cancer patients without versus with COPD (48.15% versus 35.63%; <i>P</i> = 0.037), whereas small cell lung cancer was more common in patients with COPD (23.56% versus 13.89%).
In the multivariate Cox's proportional hazard model, the adjusted hazard ratio (HRadj) was statistically significant for male sex (HRadj =5.382, 95% CI: 1.496-19.359; <i>p</i>=0.010), pathological diagnosis of adenocarcinoma (HRadj =0.460, 95% CI: 0.223-0.948; <i>p</i>=0.035), and epithelial growth factor receptor negative mutation (HRadj =6.040, 95% CI: 1.158-31.497; <i>p</i>=0.033), but not for the presence of COPD (HRadj =0.661, 95% CI: 0.330-1.325; <i>p</i>=0.24).