Table 3 (B).

Adjusted relative Odds Ratio (95% CI) of postoperative outcomes for the non-COPD group with the in-between group and the COPD group

Category	Non-COPD	In-between	COPD
Prolonged oxygen treatment	1.0	0.952 (0.453–2.000) p =0.896	2.840 (1.824–4.421) p =0.001
Prolonged postoperative stay	1.0	1.134 (0.565–2.280) p =0.723	1.836 (1.166–2.890) p =0.009
Complications	1.0	1.201 (0.570–2.531) p =0.630	1.637 (1.007–2.663) p =0.047

Adjusted Odds Ratio (OR) (95% CI) of postoperative outcomes was adjusted for age, gender, history of smoking, and operation time. Adjusted OR of postoperative outcomes of the in-between group and the COPD group were compared with those of the non-COPD group.