Kasemsuwan 1997.

Methods	Two‐arm, double‐blind, parallel‐group RCT, with 7 days duration of treatment and follow‐up
Participants	Location: Thailand, 1 site Setting of recruitment and treatment: Ramathibodi hospital (specialist hospital), Bangkok, October to December 1993 Sample size: 50 Number randomised: unclear Number completed: 19 in intervention, 16 in comparison Participant (baseline) characteristics: Age: 21 to 66 years Gender (F/M): 22 (63%)/13 (37%) Main diagnosis: mucopurulent otorrhoea High‐risk population: no 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: microscopic evaluation Confirmation of perforated tympanic membrane: not reported Presence of mucopurulent discharge: not reported Duration of symptoms (discharge): 3 months Other important effect modifiers: Alternative diagnosis of ear discharge: not reported Number who have previously had grommets inserted: not reported Number who have had previous ear surgery: not reported Number who had previous antibiotic treatment for CSOM: not reported Inclusion criteria: Any patient with a perforated tympanic membrane for longer than 3 months Any patient with mucopurulent otorrhoea Note: it is unclear if patients were included if they had a tympanic membrane perforation AND mucopurulent discharge, or if they had a tympanic membrane perforation OR mucopurulent discharge. Exclusion criteria: Cholesteatoma, pregnancy, underlying diseases, receiving antibiotics in the previous 2 weeks and during the study
Interventions	Intervention (n = 19): ciprofloxacin in saline solution (250 mg/mL), ear drops, 5 drops, 3 times daily. Duration of treatment = 7 days. Comparator group (n = 16): saline solution, ear drops. 5 drops, 3 times daily. Duration of treatment = 7 days Concurrent treatment: on day 1, 4 and 7 ear cleaning was performed. No other information regarding the concurrent treatment was provided.
Outcomes	Outcomes of interest in the review: Primary outcomes: Resolution of ear discharge ("dry ear"), measured at between 1 week and 2 weeks (7 days) Secondary outcomes: Hearing measured as the pure‐tone average of air conduction thresholds across 4 frequencies tested (at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz) of the affected ear. If this is not available, the pure‐tone average of the thresholds measured will be reported. Adverse effects from treatment Suspected ototoxicity
Funding sources	No information provided
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)	Unclear risk	Quote: "…randomly allocated treatment…" Comment: no information was provided about how the sequence was generated
Allocation concealment (selection bias)	Low risk	Quote: "…They were randomly allocated treatment with either ciprofloxacin in saline solution or solution without antibiotics in a double blind method. The medications were prepared, and given codes which were known only in the pharmaceutical laboratory." Comment: it is implied that the treatment allocation was completed by physicians without knowledge of the randomisation schedule
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Comment: it is implied that the medications were coded, rather than labelled and so the treatment group was not known by the participants or the personnel in the trial
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: it is implied that the trial was blinded and the personnel assessing the outcome (ear discharge) were unaware of the treatment allocation
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: the paper states that 15/50 (30%) participants did not complete the trial due to "lack of attendance". The paper does not provide an analysis of which group they were allocated to or why they did not attend. Given that the trial was for 7 days, this seems to be a very high dropout rate.
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol for the trial was identified through clinicaltrials.gov or the Thai registry of clinical trials. Outcomes that were detailed in the methods are presented in the full paper although the results of the audiological assessments are not presented explicitly, just as a single statement stating no difference.