TABLE 3.

Univariate and multivariate regression analysis for risk factors of SSI on training cohort

	Univariate				Multivariate
	OR	95% CI	95% CI	P value	OR	95% CI	95% CI	P value
Sex
Male	reference
Female	0.980	0.472	2.037	.957
Age	1.035	0.994	1.077	.092
BMI
<25	reference
≥25	0.790	0.382	1.635	.526
Cardiovascular disease
No	reference
Yes	1.092	0.503	2.370	.823
Number of fused vertebrae
1	reference				reference
≥2	6.397	1.892	21.629	.003*	9.222	1.500	56.688	.017*
Operative time	1.001	0.998	1.003	.680
Intraoperative blood loss	1.001	0.999	1.002	.285
Intraoperative blood transfusion	1.001	0.999	1.002	.338
Length of the incision	1.145	1.006	1.303	.040*
Duration of drain placement	1.529	1.122	2.082	.007*	1.629	1.066	2.489	.024*
Duration of diabetes (yr)
≤5	reference				reference
>5	3.296	1.373	7.912	.008*	6.226	1.655	23.423	.007*
HbA1c	1.151	0.829	1.598	.401
Preoperative blood glucose control scheme				.023*				.012*
Subcutaneous injection of insulin	reference				reference
Combined medication	8.250	1.714	39.720	.008*	3.822			.193
Oral hypoglycemic agent	2.667	0.530	13.417	.234	13.183			.022*
Diet therapy	5.508	1.194	25.415	.029*	26.442			.002*
Preoperative MFBG	1.591	1.265	2.001	.000*	1.618	1.098	2.386	.015*
Preoperative FPG‐CV	1.159	1.105	1.216	.000*	1.194	1.106	1.289	.000*
Postoperative MFBG	1.068	0.868	1.313	.536
Postoperative FPG‐CV	1.079	1.042	1.117	.000*	1.063	1.010	1.120	.022*

Note: OR odds ratio, 95% CI 95% confidence interval. *P < .05. *Statistically significant preoperative blood glucose control scheme is multi‐categorical variable, so covariate is generated for analysis.

Abbreviations: FPG‐CV: variation coefficient of fasting plasma glucose; MFBG: mean fasting blood glucose.

*Statistically significant preoperative blood glucose control scheme is multi‐categorical variable, so covariate is generated for analysis.