Table 2.

Risk factors of SSI (linear logistic regression analysis)

Variable	Odds ratio	Std error (b)	P > [z]	95%CI of OR
Clean wound	0.12	0.053	0.000	0.0525–0.2858
Clean contaminated wound	3.81	2.400	0.034	1.1091–13.0950
Contaminated wound	9.8	7.293	0.002	2.2794–42.1345
Dirty wound	10.62	6.405	0.000	3.2542–34.6368
Emergency surgery	3.55	1.555	0.004	1.5050–8.3788
Use of drain	4.76	2.755	0.007	1.5313–14.8020

CI: confidence interval, OR: odds ratio, SSI: surgical site infection