Comparison between laparoscopic uncut Roux-en-Y and Billroth II with Braun anastomosis after distal gastrectomy: A meta-analysis

Table 1 Characteristics of the included studies

Ref.	Study type	Country	Period	Number (URY/BB)	Gender (M/F)	Age (URY/BB)	BMI	ASA (I/II/III)	Tumor stage (I/II/III/IV)	Differentiation (H/M/L)	Matched factors1	NOS score
Chen[30], 2018	RCT	China	2016.5-2017.9	URY 30, BB 30	17/13, 16/14	55.00 ± 5.40, 53.50 ± 7.56	22.89 ± 4.23, 21.38 ± 2.02	NR	3/10/17/0, 4/12/14/0	5/15/10, 4/14/12	1, 2, 3, 4, 7, 8, 12	NA
Gao and Xiang[29], 2018	Retro	China	2014.1-2017.1	URY 26, BB 34	17/9, 21/13	60.61 ± 11.14, 59.72 ± 10.79	21.58 ± 1.86, 21.35 ± 1.93	NR	0/5/14/7, 0/7/18/9	8/7/11, 10/11/13	1, 2, 3, 5, 6, 9, 10, 11, 12, 13	8
Li et al[32], 2017	Retro	China	2010.1-2016.1	URY 30, BB 33	21/9, 21/12	52.81 ± 5.39, 52.09 ± 6.47	21.66 ± 2.54, 21.81 ± 2.62	NR	NG	8/11/11, 9/12/12	1, 2, 3, 5, 6, 9, 12	7
Ren et al[31], 2020	RCT	China	2015.6-2016.12	URY 44, BB 44	30/14, 28/16	59.61 ± 11.14, 59.72 ± 10.79	21.51 ± 1.86, 21.38 ± 1.93	NR	0/8/25/11, 0/9/23/12	14/13/17, 13/14/17	1, 3, 5, 6, 9, 10, 11, 13	NA
Wang et al[36], 2018	Retro	China	2015.3-2017.6	URY 81, BB 58	52/29, 46/12	56 (30-79), 56.5 (24-77)	NR	NR	41/20/17/0, 28/13/16/0	NR	1, 3, 4, 5, 6, 9	8
Wang et al[34], 2021	RCT	China	2017.1-2018.5	URY 62, BB 62	44/18, 44/18	54.84 ± 8.31; 54.69 ± 10.07	22.43 ± 3.07, 22.46 ± 3.17	27/28/7, 16/41/5	NG	NR	1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12	NA
Wu et al[33], 2021	Retro	China	2016.1-2019.4	URY 45, BB 50	27/18, 31/19	59.1 ± 6.2, 59.1 ± 6.3	23.3 ± 3.0, 23.2 ± 2.9	NR	45/0/0/0, 50/0/0/0	7/15/23, 8/19/23	1, 2, 3, 4, 5, 9, 10, 11, 12, 13	6
Zhou et al[35], 2018	Retro	China	2010.6-2015.4	URY 36, BB 39	22/14, 24/15	61 ± 5, 61 ± 8	23 ± 3, 22 ± 4	21/15/0, 23/16/0	36/0/0/0, 39/0/0/0	11/16/9, 10/19/10	2, 3, 4, 5, 6, 9, 10, 13	8

¹Outcomes: (1) Operative time; (2) Reconstruction times; (3) Intraoperative bleeding; (4) Total number of harvested lymph nodes; (5) Time to first passage of flatus or defecation; (6) Time to first solid diet; (7) Mean gastric pH at day 1; (8) Mean gastric pH at day 3; (9) Post-operative hospitalization time; (10) Anastomotic leakage; (11) Ileus; (12) Reflux gastritis; and (13) Gastroparesis.

ASA: American Society of Anesthesiologists score; BMI: Body mass index; NOS: Newcastle-Ottawa Scale; NR: Not reported; Retro: Retrospective observational study; NA: Not applicated; RCT: Randomised controlled trial; URY: Uncut Roux-en-Y; BB: BII combined Braun; NG: Not given.

Table 2 Results of risk of bias assessment (randomised controlled trials)

Ref.	Sequence generation	Allocation concealment	Blind of participant and personnel	Blind of assessment	Outcome of incomplete data	Selective report	Other bias
Chen[30], 2018	Low	Unclear	High	Unclear	Low	Unclear	Unclear
Ren et al[31], 2020	Low	Unclear	Unclear	Unclear	Low	Unclear	Unclear
Wang et al[34], 2021	Low	Low	Low	Unclear	Low	Low	Unclear

The level of bias was determined as follows: “High” indicating a risk of bias; “Unclear” indicating an uncertain risk of bias; and “Low” indicating no risk of bias.

Table 3 Subgroup analysis of all the outcomes according to study type

Subgroup	Type	No. of studies	No. of patients		Meta-analysis results		Assessment of heterogeneity
			URY	BB	OR/MD (95%CI)	P value	I²	P value
Operative time	RCTs	3	136	136	0.93 [(-5.87)-7.73]	0.79	0	0.95
	Non-RCTs	4	182	175	1.71 [(-7.09)-10.51]	0.70	0	0.82
Reconstruction time	RCTs	2	92	92	3.32 [(-3.85)-10.49]	0.36	0.92	0.0005
	Non-RCTs	4	137	156	-0.41 [(-3.85)-3.03]	0.81	0.74	0.0009
Intraoperative blood loss	RCTs	3	136	136	3.87 [(-7.02)-14.75]	0.49	0.45	0.16
	Non-RCTs	4	218	214	0.58 [(-2.60)-3.77]	0.72	0	0.91
Total number of harvested lymph nodes	RCTs	2	92	92	0.15 [(-1.86)-2.16]	0.88	0	0.98
	Non-RCTs	3	163	147	1.90 [(-0.14)-3.94]	0.07	0	0.39
Time to first passage of flatus or defecation	RCTs	2	106	106	-0.26 [(-0.87)-0.34]	0.40	0.77	0.04
	Non-RCTs	5	218	214	-0.29 [(-0.59)-0.01]	0.05	0.56	0.06
Time to first solid diet	RCTs	1	44	44	-0.05 [(-1.14)-1.04]	0.93	Not applicable
	Non-RCTs	4	173	164	-0.29 [(-0.53)-(-0.05)]	0.02	0	0.67
Postoperative hospitalization time	RCTs	2	106	106	-0.01 [(-0.16)-0.14)]	0.87	0	0.84
	Non-RCTs	5	218	214	-0.26 [(-0.78)-0.26]	0.32	0	0.63
Reflux gastritis	RCTs	2	92	92	0.03 (0.01-0.11)	< 0.00001	0	0.70
	Non-RCTs	3	193	209	0.15 (0.03-0.66)	0.01	0	0.77
Anastomotic leakage	RCTs	2	106	106	0.73 (0.15-3.48)	0.69	Not applicable
	Non-RCTs	3	107	123	1.16 (0.23-5.87)	0.85	0	0.85

URY: Uncut Roux-en-Y; BB: BII combined Braun; RCTs: Randomised controlled trials; OR: Odds ratio; MD: Mean difference; CI: Confidence interval.