Preoperative neutrophil-to-lymphocyte ratio predicts symptomatic anastomotic leakage in elderly colon cancer patients: Multicenter propensity score-matched analysis

Table 1 Patient clinical characteristics, n (%)

Variable	All patients (n = 577)	Non-AL patients (n = 541)	AL patients (n = 36)	Statistical value	P value
Gender				χ2 = 6.189	0.013
Female	276 (47.8)	266 (49.2)	10 (27.8)
Male	301 (52.2)	275 (50.8)	26 (72.2)
Age (yr)	71.0 (10.0)	71.0 (10.0)	72.0 (8.5)	Z = -1.005	0.315
BMI (kg/m2)	22.81 ± 3.43	22.79 ± 3.44	23.16 ± 3.25	t = -0.627	0.531
Smoking				χ2 = 0.866	0.352
No	393 (68.1)	371 (68.6)	22 (61.1)
Yes	184 (31.9)	170 (31.4)	14 (38.9)
History of abdominal surgery				χ2 = 0.086	0.770
No	413 (71.6)	388 (71.7)	25 (69.4)
Yes	164 (28.4)	153 (28.3)	11 (30.6)
Nonsteroidal drug use				χ2 = 0.000	1.000
No	524 (90.8)	491 (90.8)	33 (91.7)
Yes	53 (9.2)	50 (9.2)	3 (8.3)
Lung disease				χ2 = 0.061	0.804
No	316 (54.8)	297 (54.9)	19 (52.8)
Yes	261 (45.2)	244 (45.1)	17 (47.2)
Hypertension				χ2 = 2.362	0.124
No	381 (66.0)	353 (65.3)	28 (77.8)
Yes	196 (34.0)	188 (34.7)	8 (22.2)
Diabetes mellitus				χ2 = 1.203	0.273
No	486 (84.2)	458 (84.7)	28 (77.8)
Yes	91 (15.8)	83 (15.3)	8 (22.2)
Neoadjuvant chemotherapy				-1	0.124
No	567 (98.3)	533 (98.5)	34 (94.4)
Yes	10 (1.7)	8 (1.5)	2 (5.6)
Tumor location				-1	0.422
Right hemicolon	276 (47.8)	261 (48.2)	15 (41.7)
Transverse colon	29 (5.0)	28 (5.2)	1 (2.8)
Left hemicolon	64 (11.1)	57 (10.5)	7 (19.4)
Sigmoid colon	208 (36.1)	195 (36.1)	13 (36.1)
ASA classification				χ2 = 1.389	0.499
1	9 (1.6)	9 (1.7)	0 (0.0)
2	429 (74.4)	404 (74.7)	25 (69.4)
3	139 (24.0)	128 (23.6)	11 (30.6)
Surgical approach				χ2 = 4.110	0.128
Open	171 (29.6)	155 (28.7)	16 (44.4)
Laparoscopic	354 (61.4)	337 (62.2)	17 (47.2)
Robotic	52 (9.0)	49 (9.1)	3 (8.4)
Anastomosis				χ2 = 0.055	0.973
End-to-end anastomosis	198 (34.3)	185 (34.2)	13 (36.1)
End-lateral anastomosis	248 (43.0)	233 (43.1)	15 (41.7)
Lateral anastomosis	131 (22.7)	123 (22.7)	8 (22.2)
Blood transfusion intraoperatively and within 2 d postoperatively				χ2 = 20.869	< 0.001
No	427 (74.0)	412 (76.2)	15 (41.7)
Yes	150 (26.0)	129 (23.8)	21 (58.3)
T stage				-1	0.444
1	36 (6.2)	36 (6.7)	0 (0.0)
2	60 (10.4)	57 (10.5)	3 (8.3)
3	371 (64.3)	346 (64.0)	25 (69.4)
4	110 (19.1)	102 (18.8)	8 (22.3)
N stage				χ2 = 7.778	0.020
0	355 (61.5)	340 (62.9)	15 (41.7)
1	138 (23.9)	127 (23.5)	11 (30.6)
2	84 (14.6)	74 (13.7)	9 (27.7)
Tumor diameter (cm)	4.0 (3.0)	4.0 (3.0)	4.75 (2.6)	Z = -0.660	0.509
CEA (ng/mL)	3.78 (5.99)	3.66 (5.82)	5.11 (10.02)	Z = -1.468	0.142
Preoperative hemoglobin (g/L)	119.0 (40.0)	119.0 (40.0)	118.5 (32.75)	Z = -0.476	0.634
Preoperative albumin (g/L)	38.23 ± 4.69	38.40 ± 4.69	35.68 ± 3.81	t = 4.076	< 0.001
Preoperative NLR	2.62 (1.93)	2.55 (1.91)	3.36 (1.70)	Z = -3.688	< 0.001
Preoperative PNI	45.58 ± 5.94	45.86 ± 5.95	41.41 ± 3.94	t = 6.325	< 0.001

¹Variables were tested using Fisher’s exact probability method with no statistical values.

AL: Anastomotic leakage; BMI: Body mass index; ASA: American Society of Anesthesiologists; CEA: Carcinoembryonic antigen; NLR: Neutrophil-to-lymphocyte ratio; PNI: Prognostic nutritional index.

Table 2 Comparison of clinical characteristics before and after propensity score matching, n (%)

Variable	Before propensity score matching				After propensity score matching
	NLR < 2.66 (n = 295)	NLR ≥ 2.66 (n = 282)	SMD	P value	NLR < 2.66 (n = 122)	NLR ≥ 2.66 (n = 122)	SMD	P value
Gender			0.237	0.005			0.131	0.305
Female	158 (53.6)	118 (41.8)			55 (45.1)	63 (51.6)
Male	137 (46.4)	164 (58.2)			67 (54.9)	59 (48.4)
Age (yr)	70.0 (9.0)	72.0 (9.0)	0.232	0.004	70.0 (9.8)	71.0 (7.8)	0.032	0.722
BMI (kg/m2)	23.20 ± 3.49	22.40 ± 3.31	0.241	0.005	22.51 ± 3.20	22.67 ± 3.08	0.052	0.689
Smoking			0.230	0.004			0.119	0.118
No	217 (73.6)	176 (62.4)			82 (67.2)	93 (76.2)
Yes	78 (26.4)	106 (37.6)			40 (32.8)	29 (23.8)
History of abdominal surgery			0.065	0.443			0.076	0.560
No	207 (70.2)	206 (73.1)			88 (72.1)	92 (75.4)
Yes	88 (29.8)	76 (26.9)			34 (27.9)	30 (24.6)
Nonsteroidal drug use			0.022	0.795			0.063	0.641
No	267 (90.5)	257 (91.1)			111 (91.0)	113 (92.6)
Yes	28 (9.5)	25 (8.9)			11 (9.0)	9 (7.4)
Lung disease			0.214	0.010			0.117	0.364
No	177 (60.0)	139 (49.3)			67 (54.9)	74 (60.7)
Yes	118 (40.0)	143 (50.7)			55 (45.1)	48 (39.3)
Hypertension			0.047	0.573			0.018	0.891
No	198 (67.1)	183 (64.9)			82 (67.2)	83 (68.0)
Yes	97 (32.9)	99 (35.1)			40 (32.8)	39 (32.0)
Diabetes mellitus			0.100	0.207			0.022	0.864
No	254 (86.1)	232 (82.3)			101 (82.8)	102 (83.6)
Yes	41 (13.9)	50 (17.7)			21 (17.2)	20 (16.4)
Neoadjuvant chemotherapy			0.128	0.376			0.065	1.000
No	288 (97.6)	279 (98.9)			119 (97.5)	120 (98.4)
Yes	7 (2.4)	3 (1.1)			3 (2.5)	2 (1.6)
Tumor location			0.210	< 0.001			0.045	0.211
Right hemicolon	126 (42.7)	150 (53.2)			59 (48.4)	59 (48.4)
Transverse colon	8 (2.7)	21 (7.5)			2 (1.6)	8 (6.6)
Left hemicolon	30 (10.2)	34 (12.1)			17 (13.9)	19 (15.5)
Sigmoid colon	131 (44.4)	77 (27.2)			44 (36.1)	36 (29.5)
ASA classification			0.118	0.147			0.096	0.272
1	6 (2.0)	3 (1.1)			0 (0.0)	3 (2.5)
2	227 (77.0)	202 (71.6)			98 (80.3)	93 (76.2)
3	62 (21.0)	77 (27.3)			24 (19.7)	26 (21.3)
Surgical approach			0.279	< 0.001			0.099	0.330
Open	65 (22.0)	106 (37.6)			37 (30.3)	36 (29.5)
Laparoscopic	201 (68.2)	153 (54.3)			76 (62.3)	70 (57.4)
Robotic	29 (9.8)	23 (8.1)			9 (7.4)	16 (13.1)
Anastomosis			0.194	0.078			0.091	0.786
End-to-end anastomosis	114 (38.6)	84 (29.8)			40 (32.8)	35 (28.7)
End-lateral anastomosis	117 (39.7)	131 (46.5)			52 (42.6)	55 (45.1)
Lateral anastomosis	64 (21.7)	67 (23.7)			30 (24.6)	32 (26.2)
Blood transfusion intraoperatively and within 2 d postoperatively			0.318	< 0.001			0.000	1.000
No	240 (81.3)	187 (66.3)			91 (74.6)	91 (74.6)
Yes	55 (18.7)	95 (33.7)			31 (25.4)	31 (25.4)
T stage			0.339	< 0.001			0.066	0.944
1	27 (9.2)	9 (3.2)			6 (4.9)	8 (6.6)
2	36 (12.2)	24 (8.5)			11 (9.0)	12 (9.8)
3	197 (66.8)	174 (61.7)			85 (69.7)	82 (67.2)
4	35 (11.8)	75 (26.6)			20 (16.4)	20 (16.4)
N stage			0.147	0.191			0.116	0.655
0	192 (65.1)	163 (57.8)			75 (61.5)	68 (55.7)
1	63 (21.4)	75 (26.6)			29 (23.8)	34 (27.9)
2	40 (13.5)	44 (15.6)			18 (14.7)	20 (16.4)
Tumor diameter (cm)	4.00 (2.00)	5.00 (2.50)	0.427	< 0.001	4.00 (3.0)	4.75 (3.0)	0.051	0.824
CEA (ng/mL)	3.33 (4.74)	4.32 (6.97)	0.107	0.008	3.52 (5.57)	4.21 (5.59)	0.118	0.560
Preoperative hemoglobin (g/L)	126.00 (39.00)	109.50 (37.00)	0.332	< 0.001	119.5 (43.5)	117.5 (43.5)	0.035	0.711
Preoperative albumin (g/L)	39.00 ± 4.16	37.42 ± 5.06	0.311	< 0.001	38.34 ± 4.29	38.29 ± 4.77	0.009	0.944
Preoperative PNI	48.02 ± 5.22	43.04 ± 5.58	0.892	< 0.001	45.31 ± 4.99	45.16 ± 5.26	0.030	0.812

SMD: Standardized mean difference; BMI: Body mass index; ASA: American Society of Anesthesiologists; CEA: Carcinoembryonic antigen; NLR: Neutrophil-to-lymphocyte ratio; PNI: Prognostic nutritional index.

Table 3 Univariate and multivariate logistic regression analyses of risk factors associated with the occurrence of symptomatic anastomotic leakage after propensity score matching

Variable	Univariate analysis		Multivariate analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Gender
Female1
Male	1.37 (0.50-3.72)	0.540
Age (yr)	1.00 (0.91-1.09)	0.949
BMI (kg/m2)	0.98 (0.84-1.15)	0.812
Smoking
No1
Yes	0.77 (0.24-2.44)	0.653
History of abdominal surgery
No1
Yes	1.19 (0.40-3.51)	0.757
Nonsteroidal drug use
No1
Yes	1.55 (0.33-7.31)	0.581
Lung disease
No1
Yes	0.73 (0.26-2.05)	0.551
Hypertension
No1
Yes	0.86 (0.29-2.54)	0.787
Diabetes mellitus
No1
Yes	1.07 (0.29-3.89)	0.923
Neoadjuvant chemotherapy
No1
Yes	3.48 (0.37-33.03)	0.277
Tumor location
Right hemicolon1
Transverse colon	1.53 (0.17-13.61)	0.704
Left hemicolon	1.25 (0.31-4.98)	0.752
Sigmoid colon	0.92 (0.29-2.91)	0.883
ASA classification
< 21
3	1.211 (0.377-3.887)	0.748
Surgical approach
Open1
Laparoscopic	0.65 (0.22-1.94)	0.438
Robotic	1.52 (0.35-6.60)	0.574
Anastomosis
End-to-end anastomosis1
End-lateral anastomosis	1.43 (0.42-4.95)	0.568
Lateral anastomosis	1.56 (0.40-6.07)	0.523
Blood transfusion intraoperatively and within 2 d postoperatively
No1
Yes	2.85 (1.05-7.74)	0.040	2.52 (0.88-7.25)	0.049
T stage
≤ 21
≥ 3	0.822 (0.224-3.014)	0.768
N stage
01
1	1.28 (0.41-4.00)	0.667
2	1.28 (0.33-4.97)	0.725
Tumor diameter (cm)	1.01 (0.81-1.26)	0.931
CEA (ng/mL)	1.00 (0.99-1.01)	0.636
Preoperative hemoglobin (g/L)	1.01 (0.99-1.03)	0.327
Preoperative albumin (g/L)	0.85 (0.75-0.97)	0.013	0.99 (0.73-1.35)		0.946
Preoperative PNI	0.86 (0.76-0.96)	0.010	0.88 (0.66-1.17)		0.380
Preoperative NLR
NLR < 2.661
NLR ≥ 2.66	5.14 (1.44-18.38)	0.012	5.51 (1.50-20.26)		0.010

¹Control group.

BMI: Body mass index; ASA: American Society of Anesthesiologists; CEA: Carcinoembryonic antigen; NLR: Neutrophil-to-lymphocyte ratio; PNI: Prognostic nutritional index; OR: Odds ratio; CI: Confidence interval.