Impact of mechanical bowel preparation in elective colorectal surgery: A meta-analysis

Table 1 Risk of bias of studies included

Ref.	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting
Ji et al[76]	NA	NA	NA	NA	NA	NA
Chan et al[77]	NA	NA	NA	NA	NA	NA
Hu et al[64]	?	?	?	?	?	?
Bhattacharjee et al[65]	+	?	-	?	?	?
Allaix et al[74]	NA	NA	NA	NA	NA	NA
Kiran et al[29]	NA	NA	NA	NA	NA	NA
Yamada et al[66]	NA	NA	NA	NA	NA	NA
Otchy et al[67]	NA	NA	NA	NA	NA	NA
Kim et al[75]	NA	NA	NA	NA	NA	NA
Tahirkheli et al[62]	+	?	?	?	-	-
Sasaki et al[61]	+	?	?	?	?	?
Bertani et al[45]	+	+	?	?	+	+
Roig et al[68]	NA	NA	NA	NA	NA	NA
Bretagnol et al[46]	+	+	+	+	-	+
Pitot et al[69]	NA	NA	NA	NA	NA	NA
Alcantara Moral et al[47]	+	+	?	?	?	+
Miron et al[70]	NA	NA	NA	NA	NA	NA
Pena-Soria et al[48]	+	+	+	+	-	+
Leiro et al[59]	+	+	?	?	?	+
Contant et al[40]	+	+	- (2)	- (2)	-	+
Bretagnol et al[71]	NA	NA	NA	NA	NA	NA
Jung et al[49]	+	+	+	+	-	?
Veenhof et al[72]	NA	NA	NA	NA	NA	NA
Ali et al[63]	?	?	?	?	?	?
Jung et al[50]	+	+	+	+	-	?
Platell et al[51]	+	+	+	+	-	-
Fa-Si-Oen et al[52]	+	+	?	?	+	+
Bucher et al[53]	+	+	+	+	+	+
Ram et al[54]	+	- (1)	?	?	?	+
Zmora et al[37]	+	+	?	?	-	+
Young Tabusso et al[55]	?	?	- (2)	- (2)	?	?
Miettinen et al[56]	+	+	?	?	+	+
Memon et al[73]	NA	NA	NA	NA	NA	NA
Fillmann et al[60]	+	+	+	+	+	+
Burke et al[57]	?	?	+	+	-	-
Brownson et al[58]	?	?	?	?	?	?

NA: Not applicable (observational study); +: Low risk of bias; -: High risk of bias; (1): Allocation concealment utilized identification number of patient (odd or even); (2): Not blinded.

Table 2 Baseline patient demographics for all studies included

Ref.	Yearpublished	Study methodology	Study numbers		Male: Female gender		Indication for surgery	Location	Primary anastomosis	Laparoscopic approach
			MBP, n	No MBP, n	MBP	No MBP				MBP, n	No MBP, n
Ji et al[76]	2017	Observational	538	831	Unknown	Unknown	Cancer	Rectum	Y	Unknown	Unknown
Chan et al[77]	2016	Observational	159	97	85:74	55:42	Cancer	Colon and rectum	Y	159	97
Hu et al[64]	2017	RCT	76	72	Unknown	Unknown	Cancer	Colon and rectum	Y	Unknown	Unknown
Bhattacharjee et al[65]	2015	RCT	38	33	21:17	20:13	Cancer, inflammatory bowel disease, volvulus, tuberculosis	Colon and rectum	Y	0	0
Allaix et al[74]	2015	Observational	706	829	361:345	432:397	Cancer, adenoma, diverticulitis, reversal of Hartmann’s procedure, rectal prolapse	Colon and rectum	Y	829	706
Kiran et al[29]	2015	Observational	6146	2296	3030:3116	1111:1185	Unknown	Colon and rectum	N	4443	1389
Yamada et al[66]	2014	Observational	152	106	92:60	65:41	Cancer	Colon only	Y	97	64
Otchy et al[67]	2014	Observational	86	79	39:47	39:40	Cancer, diverticular disease, IBD, rectal prolapse, ischemic colitis, volvulus, colovaginal fistula	Colon and rectum	Y	37	48
Kim et al[75]	2014	Observational	1363	1112	502:694	669:610	Unknown	Colon and rectum	Y	709	472
Tahirkheli et al[62]	2013	RCT	48	48	28:20	24:24	Cancer, diverticular disease, IBD, ischemic colitis	Colon and rectum	Y	unknown	unknown
Sasaki et al[61]	2012	RCT	38	41	17:21	24:17	Cancer	Colon only	Y	29	19
Bertani et al[45]	2011	RCT	114	115	65:49	60:55	Cancer	Colon and rectum	Y	55	51
Roig et al[68]	2010	Observational	39	69	Unknown	Unknown	Cancer, diverticular disease, IBD, FAP	Colon and rectum	Y	12	20
Bretagnol et al[46]	2010	RCT	89	89	56:33	46:43	Rectal cancer	Rectum only	Y	73	74
Pitot et al[69]	2009	Observational	59	127	31:28	53:74	Cancer, diverticular disease, IBD	Colon only	Y	26	30
Alcantara Moral et al[47]	2009	RCT	70	69	41:28	48:22	Cancer	Left colon and rectum	Y	12	15
Miron et al[70]	2008	Observational	60	39	Unknown	Unknown	Unknown	Colon and rectum	Y	Unknown	Unknown
Pena-Soria et al[48]	2008	RCT	65	64	35:29:00	33:22	Cancer, IBD	Colon and rectum	Y	Unknown	Unknown
Leiro et al[59]	2008	RCT	64	65	39:25	38:27	Benign and malignant colorectal pathology	Colon and rectum	N	Unknown	Unknown
Contant et al[40]	2007	RCT	670	684	337:333	345:339	Cancer, IBD	Colon and rectum	Y	None	None
Bretagnol et al[71]	2007	Observational	61	52	42:19	32:20	Rectal cancer	Rectum only	Y	Unknown	27
Jung et al[49]	2007	RCT	686	657	306:380	317:340	Cancers, diverticular disease, adenoma	Colon only	Y	None	None
Veenhof et al[72]	2007	Observational	78	71	28:43	33:45	Not specified	Colon and rectum	Y	Unknown	Unknown
Ali et al[63]	2007	RCT	109	101	Unknown	Unknown	Unknown	Colon and rectum	Y	Unknown	Unknown
Jung et al[50]	2006	RCT	27	17	Unknown	Unknown	Cancer, adenoma and diverticular disease	Rectum only	Y	None	None
Platell et al[51]	2006	RCT	147	147	Unknown	Unknown	Cancer, IBD, diverticular disease, adenoma	Colon and rectum	N	Unknown	Unknown
Fa-Si-Oen et al[52]	2005	RCT	125	125	58:67	56:69	Cancer, diverticular disease	Colon only	Y	None	None
Bucher et al[53]	2005	RCT	78	75	47:31	34:41	Cancer, diverticular disease, reversal of Hartmann’s procedure, adenoma, endometriosis	Left colon and rectum	Y	20	22
Ram et al[54]	2005	RCT	164	165	99:65	102:63	Cancer, diverticular disease, IBD	Colon and rectum	Y	Unknown	Unknown
Zmora et al[37]	2003	RCT	187	193	103:84	94:99	Cancer, diverticular disease, IBD	Colon and rectum	Y	Unknown	Unknown
Young Tabusso et al[55]	2002	RCT	24	23	12:12	9:14	Unknown	Colon and rectum	Y	Unknown	Unknown
Miettinen et al[56]	2000	RCT	138	129	68:70	62:67	Cancer, IBD, diverticular disease	Colon and rectum	91% primary anastomosis in both arms	None	None
Memon et al[73]	1997	Observational	61	75	32:29	44:31	Cancer, diverticular disease, IBD, adenoma, lipoma	Left colon and rectum	Y	Unknown	Unknown
Fillmann et al[60]	1995	RCT	30	30	Unknown	Unknown	Cancer, diverticular disease, IBD, ischemic colitis	Colon and rectum	N	Unknown	Unknown
Burke et al[57]	1994	RCT	82	87	52:30	43:44	Cancer, diverticular disease, IBD	Left colon and rectum	Y	Unknown	Unknown
Brownson et al[58]	1992	RCT	86	93	Unknown	Unknown	Cancer and other	Colon and rectum	Y	Unknown	Unknown

FAP: Familial adenomatous polyposis; IBD: Inflammatory bowel disease; MBP: Mechanical bowel preparation; RCT: Randomised controlled trial.

Table 3 Nature of the bowel preparation used in studies included in the meta-analysis

Ref.	Details of MBP	Details of no MBP	Antibiotics given
Allaix et al[74]	PEG	Enema before left sided operations	As per local policy
Kiran et al[29]	As per local policy	Unclear	As per local policy
Yamada et al[66]	PEG	Glycerin Enema	Flomoxef at induction and 3 hourly intra op
Otchy et al[67]	PEG	Colonic resections- no MBP	Ertapenem 1 g or levofloxacin/metronidazole 500 mg 1 h post op then continued for 24 h post op
		Rectal resections- single enema
Kim et al[75]	As per local policy	Unclear	As per local policy
Tahirkheli et al[62]	Saline	No preparation	Oral ciprofloxacin plus unspecified intravenous antibiotics for 24 h post op
Sasaki et al[61]	PEG and sodium picosulphate	No preparation	Antibiotic regime not specified
Bertani et al[45]	PEG and a single enema	Single enema only	Cefotixin given at induction, 4, 12 and 24 h. Ceftriaxone and metronidazole given for 5 d post op if heavy contamination
Roig et al[68]	Mono and di sodium phosphate	No prep	Antibiotic regime not specified
Bretagnol et al[46]	Senna plus povidone-iodine enema	No prep	ceftriaxone and metronidazole at induction and every 2 hours intra op
Pitot et al[69]	PEG	Rectal resections had single enema	Antibiotic regime not specified
Alcantara Moral et al[47]	Sodium phosphate or PEG	Two preoperative enemas	Neomycin and metronidazole 1 d pre op, ceftriaxone and metronidazole at induction
Miron et al[70]	PEG and sodium sulphate	No preparation	Antibiotic regime not specified
Pena-Soria et al[48]	PEG and standard enema	No preparation	Gentamicin and metronidazole 30 min pre op and 8 hourly post op
Leiro et al[59]	Sodium di or monobasic phosphate or PEG	No preparation	Ciprofloxacin and metronidazole 500 mg pre op
Contant et al[40]	PEG and bisocodyl/ sodium phosphate	No preparation	Antibiotic regime not specified
Bretagnol et al[71]	Senna plus povidone-iodine enema	No preparation	Ceftriaxone and metronidazole at induction and every 2 h intra op
Jung et al[49]	As per local policy	No preparation	Trimethoprim + metronidazole or cef and met or dozy and met
Veenhof et al[72]	PEG	Single enema	Antibiotic regime not specified
Ali et al[63]	Saline	No preparation	Antibiotic regime not specified
Jung et al[50]	PEG or sodium phosphate	No preparation	Oral sulphamethoxazole-trimethoprim and metronidazole, cephalsporin and metronidazole, doxycycline and metronidazole
Platell et al[51]	PEG	Phosphate enema	Timentin or gentamycin and metronidazole at induction
Fa-Si-Oen et al[52]	PEG	No preparation	Ceftriaxone and metronidazole or gentamycin and metronidazole at induction
Bucher et al[53]	PEG	Rectal resections had single saline enema	Ceftriaxone and metronidazole at induction and 24 h post op
Ram et al[54]	Monobasic and dibasic sodium phosphate	No preparation	Ceftriaxone and metronidazole 1 h pre op and 48 post op
Zmora et al[37]	PEG	Rectal resections had a single phosphate enema	Erythromycin and neomycin for 3 doses and then for 24 h
Young Tabusso et al[55]	PEG or saline/mannitol	No preparation	Antibiotic regime not specified
Miettinen et al[56]	PEG	No preparation	Ceftriaxone and metronidazole at induction
Memon et al[73]	Phosphate enema, picolax, PEG, saline lavage	No preparation	Antibiotic regime not specified
Fillmann et al[60]	Mannitol	No preparation	Metronidazole and gentamicin 1 h pre op then for 48 h
Burke et al[57]	sodium picosulphate	No preparation	Ceftriaxone 1 g, metronidazole at induction and 8 and 16 h
Brownson et al[58]	PEG	No preparation	Antibiotic regime not specified

MBP: Mechanical bowel preparation; PEG: Polyethylene glycol.

Table 4 Effect of bowel preparation on outcome in patients undergoing rectal surgery

	Number of participants (MBP vs No MBP)	Odds ratio (95%CI), MBP vs No MBP	P value
Anastomotic leak	2351 (1042 vs 1309)	0.86 (0.64 to 1.15)	0.30
Surgical site infection	965 (513 vs 452)	1.22 (0.82 to 1.81)	0.33
Intra-abdominal collection	921 (486 vs 435)	0.54 (0.21 to 1.38)	0.20
Mortality	813 (419 vs 394)	0.73 (0.29 to 1.82)	0.50
Re-operation	1660 (688 vs 392)	1.57 (1.02 to 2.43)	0.04

Data from[39,45,46,50,56,57,59,71,75-77]. MBP: Mechanical bowel preparation