Preoperative bowel preparation does not favor the management of colorectal anastomotic leak

Table 1 Baseline demographic and laboratory characteristics of patients undergoing elective colorectal resection overall and by bowel preparation method

	MBP + OAB	MBP	No Prep	Overall	P value
Overall N (missing data)	n = 163 (25%)	n = 260 (39.9%)	n = 229 (35.1%)	n = 652 (100%)
Age (missing: 3/0.5%)
mean (SD)	57.69 (14.69)	60.61 (13.7)	59.48 (15.64)	59.48 (14.67)
Median	60	61	60	61	0.26
Q1/Q3	47/69	52/71	49.25/72	50/71
Age grouped n (%)
≥ 65 yr	60 (37)	104 (40.2)	98 (43)	262 (40.4)	0.50
Gender (missing: 0%)
Female	60 (36.8)	110 (42.3)	102 (44.5)	272 (41.7)	0.30
Male	103 (63.2)	150 (57.7)	127 (55.5)	380 (58.3)
BMI (missing: 2/0.3%)
Mean (SD)	28.65 (6.81)	28.94 (7.43)	28.52 (6.74)	28.72 (7.04)
Median	27.05	27.60	27.89	27.75	0.96
Q1/Q3	24.23/32.03	24.06/32.35	23.4/32.28	23.9/32.15
Race (missing: 0%)
White	120 (73.6)	214 (82.3)	149 (65.1)	483 (74.1)	< 0.001
AA	21 (12.9)	11 (4.2)	18 (7.9)	50 (7.7)
Other or unknown	22 (13.5)	35 (13.5)	62 (27.1)	119 (18.3)
ASA score (missing: 0%)
1-no disturb	3 (1.8)	3 (1.2)	9 (3.9)	15 (2.3)	0.34
2-mild disturb	68 (41.7)	110 (42.3)	91 (39.7)	269 (41.3)
3-severe disturb	86 (52.8)	139 (53.5)	116 (50.7)	341 (52.3)
≥ 4-life threat	6 (3.7)	8 (3.1)	13 (5.7)	27 (4.1)
Diabetes mellitus (missing: 0%)	30 (18.4)	30 (11.5)	37 (16.2)	97 (14.9)	0.12
Preoperative steroid use (missing: 0%)	23 (14.1)	18 (6.9)	25 (10.9)	66 (10.1)	0.05
Current smoking status (missing: 0%)	33 (20.2)	60 (23.1)	40 (17.5)	133 (20.4)	0.31
Hypertension requiring treatment (missing: 0%)	83 (50.9)	125 (48.1)	110 (48)	318 (48.8)	0.82
Preoperative weight loss > 10% in last six months (missing: 0%)	15 (9.2)	11 (4.2)	9 (3.9)	35 (5.4)	0.04
Preoperative bleeding disorder (missing: 0%)	5 (3.1)	7 (2.7)	5 (2.2)	17 (2.6)	0.86
Current procedural code
44140	23 (14.1)	56 (21.5)	46 (20.1)	125 (19.2)	0.007
44145	25 (15.3)	39 (15)	33 (14.4)	97 (14.9)
44160	15 (9.2)	17 (6.5)	34 (14.8)	66 (10.1)
44204	47 (28.8)	53 (20.4)	46 (20.1)	146 (22.4)
44205	20 (12.3)	21 (8.1)	28 (12.2)	69 (10.6)
44207	33 (20.2)	74 (28.5)	42 (18.3)	149 (22.9)
Preoperative chemotherapy (missing: 2/0.3%)	19 (11.8)	20 (7.7)	23 (10.0)	62 (9.5)	0.36
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Primary indication for surgery (missing: 0%)
Colon cancer	68 (41.7)	127 (48.8)	112 (48.9)	307 (47.1)	0.06
Non-malignant polyp	16 (9.8)	32 (12.3)	23 (10)	71 (10.9)
Inflammatory bowel disease	13 (8)	9 (3.5)	22 (9.6)	44 (6.7)
Acute diverticulitis	10 (6.1)	14 (5.4)	10 (4.4)	34 (5.2)
Chronic diverticular disease	37 (22.7)	41 (15.8)	27 (11.8)	105 (16.1)
Other	19 (11.7)	37 (14.2)	35 (15.3)	91 (14)
Preoperative hematocrit (%) (missing: 30/4.6%)
n	153 (93.9)	247 (95)	222 (96.9)	622 (95.4)
mean (SD)	38.95 (5.55)	39.14 (5.48)	38.36 (5.64)	38.82 (5.56)
Median	39	39.5	39	39.2	0.38
Q1/Q3	35.6/42.9	35.8/43	34.1/42	35.4/42.7
Preoperative white blood cells (K/cumm) (missing: 37/5.7%)
n	150 (92)	244 (93.8)	221 (96.5)	615 (94.3)
mean (SD)	7.47 (2.71)	7.52 (2.57)	7.65 (2.43)	7.56 (2.55)
Median	7.1	7	7.3	7.1	0.48
Q1/Q3	5.68/8.8	5.7/8.84	6/9	5.8/8.9
Preoperative platelets (K/cumm) (missing: 39/6%)
n	150 (92)	244 (93.8)	219 (95.6)	613 (94)
mean (SD)	265 (102)	256 (91)	267 (95)	262 (95.42)
Median	253	247	258	252	0.59
Q1/Q3	203/301	195/301	206/304	201/301
Preoperative serum albumin (g/dL) (missing: 243/37.3%)
n	112 (68.7)	164 (63.1)	133 (58.1)	409 (62.7)
mean (SD)	3.83 (0.57)	3.91 (0.53)	3.89 (0.62)	3.88 (0.57)	0.50
Median	3.9	4	4	4
Q1/Q3	3.5/4.3	3.6/4.3	3.6/4.3	3.6-4.3
Preoperative blood urea nitrogen (mg/dL) (missing: 77/11.8%)
n	149 (91.4)	231 (88.8)	195 (85.2)	575 (88.2)
mean ± SD	14.67 （8.99）	15.32 (8.55)	14.17 (6.20)	14.8 (7.96)
Median	13	14	13	14	0.18
Q1/Q3	10/16.4	11/17	10/17.7	10/17

MBP + OAB: Mechanical bowel preparation with oral antibiotics; MBP: Mechanical bowel preparation; OAB: Oral antibiotics; n: Number (%) of patients with available data; ASA: American Society of Anesthesiologists; Other: Hispanic, Asian and other; No Prep: No preparation; CPT codes 44140: Colectomy, partial, with anastomosis; 44145: Colectomy, partial, with coloproctostomy (low pelvic anastomosis); 44160: Colectomy, partial, with removal of terminal ileum with ileocolostomy; 44204: Laparoscopy, surgical, colectomy, partial, with anastomosis; 44205: Laparoscopy, surgical; colectomy, partial, with removal of terminal ileum with ileocolostomy; 44207: Laparoscopy, surgical; colectomy, partial, with anastomosis, with coloproctostomy (low pelvic anastomosis). Kruskal-Wallis test was used for continuous variables; χ² test was used for categorical variables.

Table 2 Univariable logistic regression analyses to identify factors associated with reoperation as a treatment for postoperative anastomotic leak (n = 652)

Variable		Univariable logistic regression model		P-value
	NWAD	uOR	95%CI
Bowel Prep groups
MBP vs MBP + OAB1	652 (100)	1.14	0.77-1.70	0.51
Nothing vs MBP1		1.23	0.86-1.76	0.25
Nothing vs MBP + OAB1		1.41	0.94-2.11	0.10
Age < 65 vs ≥ 65 yr1	649 (99.5)	0.82	0.60-1.12	0.21
BMI ≥ 30 vs < 301	650 (99.7)	1.44	1.03-2.00	0.03
Female vs male	652 (100)	1.35	0.99-1.85	0.06
Non-White vs White	652 (100)	1.08	0.76-1.53	0.69
No DM vs DM1	652 (100)	0.85	0.55-1.31	0.46
No steroid vs steroids1	652 (100)	0.89	0.54-1.49	0.67
Hct (%) < 38 vs ≥ 381	622 (95.4)	0.93	0.67-1.29	0.68
WBC (K/cumm) ≤ 12 vs > 121	615 (94.3)	1.53	0.74-3.16	0.26
PLT (K/cumm) < 150 vs ≥ 1501	613 (94)	1.58	0.75-3.37	0.23
Albumin (g/dL) < 3.5 vs ≥ 3.51	409 (62.7)	1.13	0.70-1.83	0.62
BUN (mg/dL) > 20 vs ≤ 201	575 (88.2)	1.17	0.73-1.88	0.53

NWAD: Number (%) of patients with available data; uOR: Unadjusted odds ratio; MBP: Mechanical bowel preparation; OAB: Oral antibiotics; BMI: Body mass index; DM: Diabetes mellitus; Hct: Hematocrit; WBC: White blood cells; PLT: Platelets; BUN: Blood urea nitrogen; OR: Odds ratios.

¹Preoperative.

Table 3 Baseline characteristics of patients undergoing elective colorectal resection, categorized based on anastomosis leak management

	Anastomosis leak treatment groups
	Non-surgical (n = 300)	Reoperation (n = 352)	Total (n = 652)	P-value
Age
NWAD (%)	300 (100)	349 (99.1)	649 (99.5)	0.891
mean ± SD	59.38 ± 15.1	59.57 ± 14.31	59.48 ± 14.67
Median (range) Q1/Q3	61 (19-88) 50/71	60 (21-89) 51/70	61 (19-89) 50/71
Height (inches)
NWAD (%)	298 (99.3)	352 (100)	650 (99.7)	0.191
mean ± SD	66.39 ± 4.02	66.8 ± 3.68	66.61 ± 3.84
Median (range) Q1/Q3	66.5 (54-80) 64/69	67 (57-76) 64/70	67 (54-80) 64/69
Weight (lbs)
NWAD (%)	299 (99.7)	352 (100)	651 (99.8)	0.021
mean ± SD	176 ± 44.29	186 ± 51.7	182 ± 48.65
Median (range) Q1/Q3	172 (95-360) 144/201	179 (83-469) 149/217	175 (83-469) 145/208
BMI
NWAD (%)	298 (99.3)	352 (100)	650 (99.7)	0.131
mean ± SD	27.99 ± 5.79	29.34 ± 7.89	28.72 ± 7.04
Median (range) Q1/Q3	27.12 (17.1-48.8) 23.9/31.3	28.1 (13.4-68.2) 23.9/33.3	27.75 (13-68) 23.9-32.15
Gender
Female	137 (45.7)	135 (38.4)	272 (41.7)	0.062
Male	163 (54.3)	217 (61.6)	380 (58.3)
Race
White	220 (73.3)	263 (74.7)	483 (74.1)	0.692
Non-White	80 (26.7)	89 (25.3)	169 (25.9)
DM
Yes	48 (16)	49 (13.9)	97 (14.9)	0.462
No	252 (84)	303 (86.1)	555 (85.1)
Steroids use
Yes	32 (10.7)	34 (9.7)	66 (10.1)	0.672
No	268 (89.3)	318 (90.3)	586 (89.9)
ASA Score
≤ 2	133 (44.3)	151 (42.9)	284 (43.6)	0.712
≥ 3	167 (55.7)	201 (57.1)	368 (56.4)
Weight loss >10%
Yes	13 (4.3)	22 (6.3)	35 (5.4)	0.282
No	287 (95.7)	330 (93.7)	617 (94.6)
PRTR
No	300 (100)	346 (98.3)	646 (99.1)	0.033
Yes	0 (0)	6 (1.7)	6 (0.9)

¹Mann-Whitney U test,

²χ² test,

³Fisher’s Exact test. BMI: Body mass index; DM: Diabetes mellitus; NWAD: Number (%) of patients with available data; ASA: American Society of Anesthesiologists; PRTR: Preoperative transfusion > 4 PRBCs in 72 h before surgery.