Relationship between body mass index and short-term postoperative prognosis in patients undergoing colorectal cancer surgery

Table 1 Basic characteristics, patient characteristics, grouping information, surgical measures, and prognosis indicators of included articles

Ref.	Country	Patient's age (years)	Obesity definition	Overall number of people	Grouping number (O/N)	Surgical measures	Outcome indicators
Hannan et al[10], 2022	Ireland	67	BMI: 30 kg/m2	107	34/73	Robotic colorectal surgery	a, b, c, d, e
Lagares-Garcia et al[11], 2016	United States	59.9 ± 13.8	BMI: 30 kg/m2	67	34/33	Robotic colorectal surgery	a, b, c, d
Akiyoshi et al[12], 2011	Japan	63.9 (23–91)	BMI: 25 kg/m2	1,169	243/926	Laparoscopic colorectal resection	a, b, e
Merkow et al[13], 2009	United States	68.02 ± 6.18	BMI: 30 kg/m2	1,679	607/1072	Laparoscopic colorectal resection	a, c, d, e
Choi et al[14], 2017	Korea	66.7 ± 11.2	BMI: 25 kg/m2	313	80/233	Laparoscopic colorectal resection	a, b, c, d, e
Zhang et al[15], 2021	China	55 (36–78)	BMI: 30 kg/m2	356	48/308	Laparoscopic colorectal resection	a, b, c, d, e
Yamashita et al[16], 2021	Japan	70 (24–96)	BMI: 25 kg/m2	1,648	313/1335	Laparoscopic colorectal resection	a, b, e
Bège et al[18], 2009	France	62 ± 10.7	BMI: 30 kg/m2	210	24/186	Laparoscopic colorectal resection	a, b, c, d, e
Hede et al[19], 2015	Sweden	72.7 ± 13.1	BMI: 30 kg/m2	6,675	1528/5147	Laparoscopic colorectal resection	a, d
Makino et al[21], 2014	United States	67.5 ± 11.7	BMI: 30 kg/m2	152	76/76	Laparoscopic colorectal resection	a, b, d, e
Bamboat et al[22], 2012	United States	65	BMI: 30 kg/m2	245	68/177	Laparoscopic colorectal resection	a, b, e
Miyamoto et al[23], 2014	Japan	65.9 ± 9.6	BMI: 25 kg/m2	561	140/421	Laparoscopic colorectal resection	a, b, d, e
Bayraktar et al[24], 2018	Turkey	60 ± 11	BMI: 30 kg/m2	101	30/71	Robotic colorectal surgery	a, b, e
Poulsen et al[25], 2012	Denmark	69 (37–97)	BMI: 30 kg/m2	425	93/332	Laparoscopic colorectal resection	a, c, d
Bell et al[26], 2018	Australia	71.6	BMI: 30 kg/m2	1464	299/1165	Laparoscopic colorectal resection	a, c, d
Peacock et al[27], 2020	United States	54.1 ± 12.5	BMI: 30 kg/m2	533	161/372	Robotic colorectal surgery	a, b, c, e

O/N: Obese/Non-obese; SSI: Surgical site infection; a: Postoperative complication rate; b: Anastomotic leak rate; c: 30-d reoperation rate; d: 30-d mortality rate; e: SSI rate.

Table 2 Quality Assessment Based on New Castle–Ottawa Scale

Ref.	Case selection (/4)	Comparability (/2)	Outcome indicators (/3)	Total score (/9)
Hannan et al[10], 2022	4	2	3	9
Lagares-Garcia et al[11], 2016	4	2	2	8
Akiyoshi et al[12], 2011	4	2	2	8
Merkow et al[13], 2009	4	2	3	9
Choi et al[14], 2017	4	2	2	8
Zhang et al[15], 2021	4	2	2	8
Yamashita et al[16], 2021	4	2	3	9
Bège et al[18], 2009	4	2	2	8
Hede et al[19], 2015	4	2	3	9
Makino et al[21], 2014	3	2	2	7
Bamboat et al[22], 2012	3	2	2	7
Miyamoto et al[23], 2014	2	2	2	6
Bayraktar et al[24], 2018	2	2	2	6
Poulsen et al[25], 2012	3	2	2	7
Bell et al[26], 2018	2	2	2	6
Peacock et al[27], 2020	4	2	2	8

Table 3 Subgroup analysis of indicators of overall complication incidence after surgery

Grouping number	Subgroup grouping method	Subgroup	Number of articles	Effect size	Heterogeneity
					I2 (%)	tau2
1	Geographical location	Europe	6	OR = 1.59, (1.40, 1.80)	0	0
		North America	5	OR = 1.14, (0.94, 1.37)	0	0
		Asia	5	OR = 1.13, (0.84, 1.52)	35.4	0.04
2	Surgery approach	Robotic colorectal surgery	4	OR = 1.18, (0.85, 1.64)	0	0
		Laparoscopic colorectal resection	12	OR = 1.28, (1.08, 1.51)	53.3	0
3	Obese body mass index	30 kg/m2	12	OR = 1.34, (1.14, 1.57)	21.8	0.02
		25 kg/m2	4	OR = 1.14, (0.81, 1.58)	51.3	0.06