Yuen 1994.

Study characteristics
Methods	Non‐blinded, parallel‐group RCT, with 1 week of treatment and a total of 2 weeks follow‐up
Participants	Location: Hong Kong, 1 site Setting of recruitment and treatment: outpatient clinic of the Otorhinolaryngology Unit, the University of Hong Kong, Queen Mary Hospital between October 1991 and February 1993 Sample size: 60 Number randomised: 30 in ofloxacin group, 30 in amoxicillin‐clavulanic acid group Number completed: 29 in ofloxacin group, 27 in amoxicillin‐clavulanic acid group Participant (baseline) characteristics: Age: 18 to 70 years with a median of 35 years Gender (F/M): 33 (55%)/23 (45%) Main diagnosis: active chronic suppurative otitis media with central perforation High‐risk population: Cleft palate (or other craniofacial malformation): not reported Down syndrome: not reported Indigenous groups (Australian Aboriginals/Greenland natives): not reported Immunocompromised: not reported Diagnosis method: Confirmation of perforated tympanic membrane: size of perforation documented Presence of mucopurulent discharge: 39/60 Duration of symptoms (discharge): not reported Other important effect modifiers: Alternative diagnosis of ear discharge: none Number who have previously had grommets inserted: none Number who have had previous ear surgery: not reported Number who had previous antibiotic treatment for CSOM: not reported Inclusion criteria: Active chronic suppurative otitis media with central perforation Exclusion criteria: Cholesteatoma Discharging mastoid cavity Large aural polyp Acute traumatic perforation Acute otitis media Presence of a grommet History of radiotherapy of temporal bone and otomycosis All patients had no prior antibiotic treatment for at least 1 week before commencement of treatment
Interventions	Intervention (n = 30): 0.3% ofloxacin ear drops 3 times daily for 1 week Comparator group(n = 30): oral amoxicillin‐clavulanic acid (375 mg) 3 times daily for 1 week Concurrent treatment: suction clearance of aural pus under microscopy (conducted after obtaining microbiology sample at baseline)
Outcomes	Outcomes of interest in the review: Primary outcomes: Complete resolution of ear discharge, measured at between 1 to 2 weeks Pain (otalgia) Secondary outcomes: Hearing loss (pure‐tone audiograms were carried out before commencement and after completion of treatment) Suspected ototoxicity (tinnitus, hearing loss, dizziness)
Funding sources	"This study was supported in part by a grant (No. 335/048/0040) from the committee on research and conference grants of the University of Hong Kong."
Declarations of interest	No information provided
Notes	Unit of randomisation: person Methods for including patients with bilateral disease: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "patients were randomized to two groups by drawing concealed envelopes." Comment: adequate randomisation sequence generation.
Allocation concealment (selection bias)	Low risk	Quote: "patients were randomized to two groups by drawing concealed envelopes." Comment: no further information about how the allocation was concealed (e.g. opaque envelope) but should be adequate
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: no blinding or placebo mentioned – should be unblinded study
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The patients were instructed for the documentation of the degree of severity (graded into mild, moderate, and severe) of symptoms of otalgia, tinnitus, hearing loss, dizziness, and aural discharge daily for 2 weeks on a card…" Comment: patients were the main assessors of outcomes – not blinded and most outcomes were subjective
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: 1/30 (3%) in the ofloxacin group and 2/30 (7%) in the amoxicillin‐clavulanic acid group defaulted visits. One patient in the amoxicillin‐clavulanic acid group stopped treatment early due to adverse effects. The attrition percentage was small and clearly documented.
Selective reporting (reporting bias)	Unclear risk	Comment: no published protocol was found. Some of the outcomes described as collected in the methods section were not fully reported, e.g. otalgia, degree of severity.

CSOM: chronic suppurative otitis media; F: female; M: male; RCT: randomised controlled trial; WHO: World Health Organization