Van Hasselt 1998b.

Methods	Three‐arm, double‐blind, parallel‐group RCT, with a single application treatment and 1‐week duration of follow‐up
Participants	Location: Malawi, rural, unclear no of sites Setting of recruitment and treatment: community‐based, study presented in 1998 Sample size: Number randomised: unclear Number completed: 79 ears in ofloxacin, 91 ears in antiseptic, 83 ears in HPMC alone Participant (Baseline) characteristics: Age: Not reported (NR) Gender (F/M): NR Main diagnosis: CSOM High‐risk population: not reported, but rural areas in Malawi Cleft palate (or other craniofacial malformation): NR Down syndrome: NR Indigenous groups (Australian Aboriginals/Greenland natives): NR Immunocompromised: NR Diagnosis method: Confirmation of perforated tympanic membrane: NR Presence of mucopurulent discharge: NR Duration of symptoms (discharge): NR Other important effect modifiers: Alternative diagnosis of ear discharge: NR Number who have previously had grommets inserted: NR Number who have had previous ear surgery: NR Number who had previous antibiotic treatment for CSOM: NR Inclusion criteria: NR Exclusion criteria: NR
Interventions	Intervention 1 (n = unclear): 0.075% ofloxacin in hypromellose (hydroxypropyl methyl‐cellulose (HPMC)) 1.5%, single application (no details of quantity) Intervention 2 (n = unclear): 1% povidone Iodine in 1.5% hypromellose (HPMC), single application (no details of quantity) Intervention 3 (n = unclear): 1.5% hypromellose (HPMC), single application (no details of quantity) Concurrent treatment: suction cleaning in all groups (no information about methods used) before the first treatment. No other information.
Outcomes	Outcomes of interest in the review: Primary outcomes: Resolution of ear discharge or "dry ear" measured at between 1 week to 2 weeks. Unclear if otoscopically confirmed. Secondary outcomes: NR
Funding sources	No information provided – other studies by the authors were funded by Christian Blind Mission
Declarations of interest	No information provided
Notes	Unit of randomisation: unclear, probably by ear Methods for reporting outcomes of patients with bilateral disease: counting bilateral ears separately, but number of patients per group was not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Randomised" Comment: no information about sequence generation. A lack of baseline characteristics makes it difficult to determine whether there was likely to be bias caused due to the random sequence generation. Unclear if this was randomised by person or by ear.
Allocation concealment (selection bias)	Unclear risk	Comment: no information about allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "Double‐blind" Comment: authors state that the trial was double‐blind and the treatment schedules were all the same. Blinding would be possible to do so with ofloxacin and hypromellose alone, however the iodine drops should look different. There is no mention how blinding was achieved.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "Double‐blind" Comment: authors state that the trial was double‐blind and the treatment schedules were all the same.
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: there is no information regarding the number of people starting the trial and so it is not possible to determine whether there was a dropout rate during the trial and whether that could have impacted the results.
Selective reporting (reporting bias)	High risk	Comment: the study was not published and was only presented as a conference presentation which cannot be accessed. The information comes from a paragraph in the introduction of a separate paper and so it is not possible to evaluate the methods fully due to lack of information presented. No protocol was available on the WHO clinical trials registry.

CSOM: chronic suppurative otitis media; F: female; HPMC: hydroxypropyl methyl‐cellulose; M: male; NR: not reported; RCT: randomised controlled trial; WHO: World Health Organization