Comparison 2. 5‐ASA versus control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2.1 Postoperative infection within 30 days of surgery	6	5030	Odds Ratio (IV, Random, 95% CI)	0.76 [0.51, 1.14]
2.1.1 Unadjusted Analysis	6	5030	Odds Ratio (IV, Random, 95% CI)	0.76 [0.51, 1.14]
2.2 Postoperative infection within 30 days of surgery: subgroup UC vs CD	5		Odds Ratio (IV, Random, 95% CI)	0.63 [0.45, 0.89]
2.2.1 Ulcerative colitis	1		Odds Ratio (IV, Random, 95% CI)	0.50 [0.26, 0.96]
2.2.2 Crohn's disease	4		Odds Ratio (IV, Random, 95% CI)	0.70 [0.45, 1.07]
2.3 Postoperative infection within 30 days of surgery: subgroup pre 1998 versus 1998 or after	6		Odds Ratio (IV, Random, 95% CI)	0.76 [0.51, 1.14]
2.3.1 Pre 1998	1		Odds Ratio (IV, Random, 95% CI)	1.08 [0.47, 2.51]
2.3.2 1998 or after	5		Odds Ratio (IV, Random, 95% CI)	0.71 [0.45, 1.14]
2.4 Incisional infections and wound dehiscence	1		Odds Ratio (IV, Random, 95% CI)	0.53 [0.30, 0.95]
2.5 Intra‐abdominal infectious complications	3		Odds Ratio (IV, Random, 95% CI)	0.77 [0.45, 1.33]
2.6 Postoperative infection within 30 days of surgery: sensitivity exclude abstract	6		Odds Ratio (IV, Random, 95% CI)	0.76 [0.51, 1.14]
2.7 Postoperative infection within 30 days of surgery: sensitivity excluding surgery for abscess	2		Odds Ratio (IV, Random, 95% CI)	0.79 [0.36, 1.73]
2.7.1 Unadjusted Analysis	2		Odds Ratio (IV, Random, 95% CI)	0.79 [0.36, 1.73]