Table 4. Results of subgroup analyses for IH at the six-month and one-year follow-ups.

All outcomes are stratified according to study design (RCTs or observational), mesh location (onlay, retrorectus, preperitoneal, and intraperitoneal), mean BMI (<40 and >40), and study population (bariatric, neoplastic, vascular, and mixed). The value of I² shows the heterogeneity among subgroups.

P_subgroup represents p-values between subgroups.

IH, incisional hernia; OR, odds ratio; No Sig. Diff., no significant difference; Sig. Diff., Significant difference.

Subgroups	IH at 6-months follow-up					IH at 1-year follow-up
	N studies	I2 (%)	OR [95% CI]	Psubgroup	Comments	N studies	I2 (%)	OR [95% CI]	Psubgroup	Comments
Study design
RCT	2	0	1.26 [0.55, 2.91]	0.49	No Sig. Diff.	5	86	0.14 [0.03, 0.82]	0.70	No Sig. Diff.
Observational	1	-	0.43 [0.02, 8.34]			3	0	0.21 [0.08, 0.59]
Mesh location
Onlay	1	-	0.43 [0.02, 8.34]	0.49	No Sig. Diff.	3	50	0.13 [0.03, 0.52]	0.28	No Sig. Diff.
Retrorectus	-	-	-			2	0	0.07 [0.01, 0.38]
Preperitoneal	2	0	1.26 [0.55, 2.91]			2	59	0.60 [0.11, 3.14]
Intraperitoneal	-	-	-			1	-	0.10 [0.02, 0.47]
Mean BMI
<40	1	-	0.43 [0.02, 8.34]	0.49	No Sig. Diff.	2	0	0.08 [0.02, 0.32]	0.11	No Sig. Diff.
>40	2	0	1.26 [0.55, 2.91]			5	60	0.33 [0.11, 1.00]
Study population
Bariatric	2	0	1.26 [0.55, 2.91]	0.49	No Sig. Diff.	4	63	0.30 [0.07, 1.36]	0.58	No Sig. Diff.
Neoplastic	-	-	-			2	75	0.12 [0.02, 0.81]
Vascular	-	-	-			1	-	0.04 [0.00, 0.72]
Mixed	1	-	0.43 [0.02, 8.34]			1	-	0.10 [0.02, 0.47]