Comparison 1. Corticosteroids versus control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Postoperative infection within 30 days of surgery	41		Odds Ratio (IV, Random, 95% CI)	Subtotals only
1.1.1 Adjusted Analysis	17		Odds Ratio (IV, Random, 95% CI)	1.70 [1.38, 2.09]
1.1.2 Unadjusted Analysis	24		Odds Ratio (IV, Random, 95% CI)	1.22 [1.03, 1.45]
1.2 Postoperative infection within 30 days of surgery: subgroup UC vs CD	33		Odds Ratio (IV, Random, 95% CI)	1.36 [1.18, 1.57]
1.2.1 Ulcerative colitis	11		Odds Ratio (IV, Random, 95% CI)	1.49 [1.10, 2.02]
1.2.2 Crohn's disease	23		Odds Ratio (IV, Random, 95% CI)	1.32 [1.11, 1.57]
1.3 Postoperative infection within 30 days of surgery: subgroup pre 1998 versus 1998 or after	15		Odds Ratio (IV, Random, 95% CI)	1.72 [1.37, 2.16]
1.3.1 Pre 1998	2		Odds Ratio (IV, Random, 95% CI)	4.22 [1.67, 10.64]
1.3.2 1998 or after	13		Odds Ratio (IV, Random, 95% CI)	1.62 [1.30, 2.01]
1.4 Incisional infections and wound dehiscence	7		Odds Ratio (IV, Random, 95% CI)	1.41 [0.72, 2.74]
1.5 Intra‐abdominal infectious complications	28		Odds Ratio (IV, Random, 95% CI)	1.53 [1.28, 1.84]
1.6 Extra‐abdominal infections	4		Odds Ratio (IV, Random, 95% CI)	1.23 [0.97, 1.55]
1.7 Postoperative infection within 30 days of surgery: sensitivity excluding very high risk of bias	15		Odds Ratio (IV, Random, 95% CI)	1.43 [1.13, 1.81]
1.8 Postoperative infection within 30 days of surgery: sensitivity exclude abstract	36		Odds Ratio (IV, Random, 95% CI)	1.48 [1.28, 1.72]
1.9 Postoperative infection within 30 days of surgery: sensitivity excluding surgery for abscess	21		Odds Ratio (IV, Random, 95% CI)	1.37 [1.14, 1.65]
1.9.1 Adjusted Analysis	9		Odds Ratio (IV, Random, 95% CI)	1.79 [1.35, 2.38]
1.9.2 Unadjusted Analysis	12		Odds Ratio (IV, Random, 95% CI)	1.07 [0.81, 1.40]