Wang 2012.

Methods	Design: randomised, placebo‐controlled, parallel‐group trial
Participants	Number assigned: 45 adults and elderly (macrolide n = 23, placebo n = 22) Age in years (mean (range)): macrolide: 60 (27 to 80), placebo: 55 (27 to 80) Setting: secondary care
Interventions	Indication: non‐eosinophilic refractory asthma Type of macrolide: clarithromycin Route: per oral Dose per day: 1000 mg Duration of treatment: 56 days Total treatment dose: 56,000 mg
Outcomes	Adverse events stated as an outcome in trial registration/protocol/paper: unclear Adverse events ascertainment: participants asked Adverse events: not reported Antimicrobial resistance: not reported Death: not reported
Funding sources	None stated.
Notes	Concomitant medication: yes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Sequence generation not described.
Allocation concealment (selection bias)	Unclear risk	Allocation not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Unclear if placebo was identical appearing
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear if participants and clinicians were blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	1 participant dropped out, reason unclear.
Selective reporting (reporting bias)	High risk	Adverse events not clearly stated as an outcome. Standardised ascertainment. However, no reporting about adverse events.
Other bias	Low risk	None were identified.