Table 3.

Firth’s bias-reduced logistic regression analyses of the risk factors for BPF

Covariates	Estimate	Standard error	p-value	X2	95% Cl
TPF (0: no, 1: yes)	− 1.011	0.857	0.256	1.596	− 3.257–0.489
Operation side (0: left, 1: right)	0.881	0.541	0.115	2.478	− 0.223–1.967
Re-operation (0: no, 1: yes)	1.000	0.768	0.202	1.631	− 0.583–2.419
Surgical approach (0: thoracotomy, 1: VATS)	− 1.072	1.445	0.402	0.702	− 5.955–1.104