Schils 2017.

Study characteristics
Methods	Matched retrospective cohort study. Study period 2006 to 2016
Participants	Country: Belgium. CD patients who underwent right hemicolectomy with ileocolonic anastomosis
Interventions	1. Preoperative vedolizumab (n= 12) within 14 weeks of surgery 2. Preoperative anti‐TNF therapy (n= 12) within 8 weeks of surgery 3. Preoperative steroids (n= 12) 4. No preoperative therapy (n= 12)
Outcomes	Infectious complications and anastomotic leak within 30 days of surgery
Notes	This study is an abstract. Additional information was provided by the authors of Schils et al. NOS low risk of bias overall.
Risk of bias
Bias	Authors' judgement	Support for judgement
Representativeness of the exposed cohort	Low risk	CD patients who underwent right hemicolectomy with ileocolonic anastomosis from 2006 to 2016
Selection of the non exposed cohort	Low risk	Both groups obtained from the same database and time period. Matched for age and gender
Ascertainment of exposure	Low risk	Medical charts were reviewed
Demonstration that outcome of interest was not present at start of study	Unclear risk	Information not provided
Comparability of cohorts (Controlled for critical factor/other medications)	High risk	Did not control for other medications
Comparability of cohorts (Controlled for additional factor)	Low risk	Controlled for age and gender
Assessment of outcome	Low risk	Medical charts were reviewed
Was follow‐up long enough for outcomes to occur	Low risk	30 days
Adequacy of follow up of cohorts	Unclear risk	Information not provided