West 2004.

Methods	Randomized controlled trial with blinded investigators and participants Intention to treat Eighteen week trial
Participants	Patients aged with a diagnosis of CD that was complicated by at least one perianal fistula (N = 24)
Interventions	Patients were randomised to receive oral ciprofloxacin 500 mg twice daily (n = 11) or oral placebo (n = 13) All patients also received 5 mg/kg infliximab at weeks 6, 8, and 12. Three patients received intravenous hydrocortisone prior to infliximab infusion
Outcomes	Primary outcome: Clinical response (50% or greater reduction in draining fistulae confirmed by no drainage despite firm finger compression) Secondary outcomes: PDAI and 3D endoscopic ultrasound with 3% hydrogen peroxide used as a contrast medium
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Both patients and investigators were blinded to treatment assignments
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Both patients and investigators were blinded to treatment assignments
Incomplete outcome data (attrition bias) All outcomes	Low risk	Rate of discontinuation was similar in both treatment groups 2/11 in ciprofloxacin group and 2/13 in placebo group
Selective reporting (reporting bias)	Low risk	All expected outcomes were reported
Other bias	Low risk	No other apparent sources of bias