Comparison 2. Mass versus layered closure.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Incisional hernia	5	1176	Risk Ratio (M‐H, Random, 95% CI)	1.92 [0.58, 6.35]
1.1 Same closure technique and suture material in each group	1	206	Risk Ratio (M‐H, Random, 95% CI)	3.86 [1.34, 11.07]
1.2 Different closure technique or suture material in each group	4	970	Risk Ratio (M‐H, Random, 95% CI)	1.47 [0.33, 6.67]
2 Wound infection	11	2926	Risk Ratio (M‐H, Random, 95% CI)	0.93 [0.67, 1.30]
2.1 Same closure technique and suture material in each group	1	282	Risk Ratio (M‐H, Random, 95% CI)	1.26 [0.79, 2.02]
2.2 Different closure technique or suture material in each group	10	2644	Risk Ratio (M‐H, Random, 95% CI)	0.89 [0.62, 1.28]
3 Wound dehiscence	11	2863	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.31, 1.52]
3.1 Same closure technique and suture material in each group	1	282	Risk Ratio (M‐H, Random, 95% CI)	0.46 [0.04, 5.01]
3.2 Different closure technique or suture material in each group	10	2581	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.28, 1.68]
4 Sinus or fistula formation	6	1076	Risk Ratio (M‐H, Random, 95% CI)	0.49 [0.15, 1.62]
4.1 Same closure technique and suture material in each group	1	282	Risk Ratio (M‐H, Random, 95% CI)	0.92 [0.13, 6.43]
4.2 Different closure technique or suture material in each group	5	794	Risk Ratio (M‐H, Random, 95% CI)	0.44 [0.10, 1.83]