van Hasselt 1998a.

Methods	Four‐arm, double‐blind, parallel‐group RCT, with 2‐week duration of treatment and 8‐week duration of follow‐up
Participants	Location: Malawi, rural, unclear number of sites Setting of recruitment and treatment: community‐based, study presented in 1998 Sample size: 107 children (151 ears) Number randomised: unclear Number completed: unclear Participant (baseline) characteristics: Age: not specified ‐ "mainly children" Gender (F/M): not reported Main diagnosis: CSOM for more than 2 months 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: not reported Presence of mucopurulent discharge: not reported Duration of symptoms (discharge): 2 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: CSOM for more than 2 months Exclusion criteria: Uncooperative with suction cleaning
Interventions	Intervention 1: neomycin/polymyxin‐B, ear drops, no information on concentration, 6 drops/7 days. Duration of treatment = 2 weeks. Intervention 2: neomycin/polymyxin‐B, ear drops, no information on concentration, 6 drops/12 hours. Duration of treatment = 2 weeks. Intervention 3: ofloxacin 0.3%, ear drops, 6 drops/7 days. Duration of treatment = 2 weeks. Intervention 4: ofloxacin 0.3%, ear drops, 6 drops/12 hours. Duration of treatment = 2 weeks. Concurrent treatment: weekly suction cleaning in all groups (no information about methods used). 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, 2 to 4 weeks and after 4 weeks. Unclear if otoscopically confirmed. Secondary outcomes: Not reported
Funding sources	No information provided
Declarations of interest	No information provided
Notes	Unit of randomisation: unclear Methods for reporting outcomes of patients with bilateral disease: counting bilateral ears separately
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 bias due to the randomisation sequence generation
Allocation concealment (selection bias)	Unclear risk	Comment: no information about allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Double‐blind" Comment: authors state that the trial was double‐blind but the treatment regimens were not the same (once weekly versus twice daily) and there was no mention of placebo used
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "Double‐blind" Comment: authors state that the trial was double‐blind but the treatment regimens were not the same (once weekly versus twice daily) and there was no mention of placebo used
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: the number of "defaulting ears" was 15% at 8 weeks, however it is not possible to determine whether the people that "defaulted" were evenly balanced across the different treatment groups. No reasons are provided for dropouts.
Selective reporting (reporting bias)	High risk	Comment: the study was not published and was only reported as a conference presentation. 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; RCT: randomised controlled trial; WHO: World Health Organization