Amland 1995.

Methods	Design: randomised, placebo‐controlled, parallel‐group trial
Participants	Number assigned: 339 children, adults, and elderly (macrolide n = 171, placebo n = 168) Age in years mean (range): male: macrolide: 30 (7 to 85), placebo: 28 (6 to 84); female: macrolide 33 (6 to 84), placebo: 33 (7 to 82) Setting: secondary care
Interventions	Indication: prevention of postoperative wound infections Type of macrolide: azithromycin Route: per oral Dose per day: 1000 mg (maximum) Duration of treatment: 1 day Total treatment dose: 1000 mg (maximum)
Outcomes	Adverse events stated as an outcome in trial registration/protocol/paper: no Adverse events ascertainment: unclear Adverse events: data reported Antimicrobial resistance: not reported Death: not reported
Funding sources	None stated. Reports that the study was supported by Pfizer, who provided the study medication
Notes	Concomitant medication: yes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was performed in blocks of 10 using a computer‐generated chart.
Allocation concealment (selection bias)	Low risk	Central allocation
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Placebo not described.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear if participants and clinicians were blinded to treatment groups
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low dropout, similar across groups
Selective reporting (reporting bias)	Unclear risk	Adverse events not stated as an outcome, unclear ascertainment. However, adverse events reported.
Other bias	Low risk	None were identified.