Myrelid 2014.

Study characteristics
Methods	Retrospective cohort. Study period not provided
Participants	Country: Sweden. CD patients who underwent resection with primary anastomoses and/or stirctureplasties. Patients with stomas were excluded
Interventions	1. Preoperative infliximab (n= 111) within 2 months of surgery 2. No preoperative infliximab (n= 187)
Outcomes	Infectious complications within 30 days of surgery
Notes	NOS very high risk of bias overall Unadjusted ORs for preoperative steroids, immunomodulators and anti‐TNF were o btained from regression analysis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Representativeness of the exposed cohort	Low risk	CD patients who underwent resection with primary anastomoses and/or stirctureplasties.
Selection of the non exposed cohort	Low risk	Both groups obtained from the same hospital database and time period
Ascertainment of exposure	Low risk	Data obtained from database
Demonstration that outcome of interest was not present at start of study	High risk	Indication for surgery was abscess/fistula in 61 patients
Comparability of cohorts (Controlled for critical factor/other medications)	High risk	Univariate analysis
Comparability of cohorts (Controlled for additional factor)	High risk	Univariate analysis
Assessment of outcome	Low risk	Data obtained from database
Was follow‐up long enough for outcomes to occur	Low risk	30 days
Adequacy of follow up of cohorts	Unclear risk	No information provided