Predicting surgical site infections using a novel nomogram in patients with hepatocelluar carcinoma undergoing hepatectomy

Table 1 Baseline characteristics of the cohorts

	Training cohort (n = 309)		Validation cohort (n = 331)		P-value
	No. of patients	Percent	No. of patients	Percent
Gender					0.197
Male	266	86.1	296	89.4
Female	43	13.9	35	10.6
Age, yr					0.095
Median	56		55
IQR	48-63		48-61
BMI, kg/m2					0.111
Median	22.7		23.0
IQR	20.6-24.8		21.1-27.2
ASA score					0.395
1	61	19.7	80	24.2
2	210	68.0	214	64.6
3	38	12.3	37	11.2
Smoking					0.241
Yes	136	44.0	161	48.6
No	173	56.0	170	51.4
Alcohol consumption					0.140
Yes	159	51.5	151	45.6
No	150	48.5	180	54.4
Diabetes					0.616
Yes	29	9.4	35	10.6
No	280	90.6	396	89.4
Etiology					0.204
Hepatitis B	227	73.5	243	73.4
Hepatitis C	12	3.9	7	2.1
Child-Pugh grade					0.562
A	295	95.5	319	96.4
B and C	14	4.5	12	3.6
TNM stage					0.201
I	148	47.9	139	42.0
II	114	36.9	125	37.8
IIIa	17	5.5	34	10.2
IIIb	28	9.1	30	9.1
IVa	2	0.6	3	0.9
IVb	0	0	0	0
Cirrhosis					0.130
Yes	218	70.6	215	65.0
No	91	29.4	116	35.0
AFP, ng/mL					0.876
Median	65.8		74.8
IQR	8.7-479.8		8.4-754.2
ALT, U/L					0.126
Elevated	109	35.3	98	29.6
Normal	200	64.7	232	70.4
AST, U/L					0.219
Elevated	139	44.9	133	40.2
Normal	170	55.1	198	59.8
Albumin, g/L					0.316
Median	40.6		40.1
IQR	36.7-43.9		37.5-42.7
TB, μmol/L					0.410
Median	14.2		14.7
IQR	11.3-18.6		11.6-18.4
INR					0.792
Median	1.04		1.04
IQR	0.98-1.10		0.98-1.10
Hb, g/L					0.504
Median	145		147
IQR	132-156		135-155
PLT, 109/L					0.141
Median	142		138
IQR	106-192		102-178
ICG15%					0.775
Median	5.4		5.8
IQR	3.0-8.6		2.8-8.5
History of RFA					0.228
Yes	13	4.2	21	6.3
No	296	95.8	310	93.7
History of TACE					0.584
Yes	8	2.6	11	3.3
No	301	97.4	320	96.7
Repeat hepatectomy					0.868
Yes	48	15.6	53	16.0
No	261	84.4	278	84.0
Type of hepatectomy					0.109
Major	81	35.2	69	20.8
Minor	228	64.8	262	79.2
Duration of surgery, min					0.351
Median	237		223
IQR	184-302		183-292
Blood Loss, mL					0.215
Median	160		220
IQR	80-400		110-330
Intraoperative blood transfusion					0.305
Yes	63	20.4	57	17.2
No	246	79.6	274	82.8
Surgical site infection					0.840
Yes	33	10.7	37	11.2
Grade II	21	6.8	23	6.9
Grade IIIa	7	2.3	9	2.7
Grade IIIb	2	0.6	1	0.3
Grade IVa	2	0.6	2	0.6
Grade IVb	0	0	1	0.3
Grade V	1	0.3	1	0.3
No	276	89.3	294	88.8
Hospital stay, d					0.323
Median	8		8
IQR	6-11		6-12

BMI: Body mass index; ADL: Activities of daily living; AFP: Alpha-protein; TB: Total bilirubin; INR: International normalized ratio; Hb: Hemoglobin; PLT: Platelets; SSI: Surgical site infection; RFA: Radiofrequency ablation; TACE: Transcatheter arterial chemoembolization.

Table 2 Univariate and multivariate analyses of risk factors for surgical site infections in the training cohort

	Univariate analysis			Multivariate analysis
	OR	95%CI	P-value	OR	95%CI	P-value
Gender	0.600	0.278-1.297	0.192
Age, yr	0.975	0.941-1.010	0.282
BMI, kg/m2	1.004	0.894-1.129	0.930
ASA score > 2	2.674	1.346-5.315	0.006	4.518	1.528-13.360	0.006
Smoking	0.862	0.499-1.653	0.654
Alcohol consumption	1.002	0.526-1.911	0.994
Diabetes	0.966	0.314-2.970	0.951
Child-Pugh grade	1.044	0.840-1.298	0.655
TNM stage	1.174	0.873-1.416	0.247
Cirrhosis	0.960	0.476-1.935	0.909
Elevated ALT, U/L	1.193	0.618-2.303	0.600
Elevated AST, U/L	1.299	0.682-2.476	0.425
Albumin, g/L	0.789	0.721-0.836	0.001	0.900	0.817-0.992	0.033
TB, μmol/L	0.989	0.968-1.011	0.071
Hb, g/L	1.007	0.987-1.027	0.145
History of RFA	1.554	0.329-7.337	0.575
History of TACE	1.201	0.143-9.071	0.866
Repeat hepatectomy	2.364	1.203-4.646	0.013	3.859	1.435-10.381	0.007
Type of hepatectomy	2.649	1.406-4.994	0.002	1.277	0.506-3.228	0.605
Duration of surgery, min	1.009	1.006-1.013	< 0.001	1.011	1.007-1.015	< 0.001
Blood loss, mL	1.001	1.000-1.002	0.002	1.001	0.999-1.002	0.329
Intraoperative blood transfusion	1.464	0.717-2.991	0.299

BMI: Body Mass Index; TB: Total bilirubin; Hb: Haemoglobin; SSI: Surgical site infections; RFA: Radiofrequency ablation; TACE: Transcatheter arterial chemoembolization.

Table 3 Risk groups based on the predicted nomogram

Group	Total points	Predicted risk	Predicted mean risk (95%CI)	Observed rate
Low-risk	< 70	< 10%	7.46 (7.34-7.60)	2.8% (12/429)
Intermediate-risk	70-104	10%-50%	21.42 (20.01-22.83)	21.6% (40/185)
High-risk	> 104	> 50%	71.07 (65.84-76.29)	69.2% (18/26)