Battaglia 2008.

Study characteristics
Methods	Double‐blind, parallel‐group randomised controlled trial with 3 weeks duration of treatment and 7 weeks duration of follow‐up
Participants	Setting: multicentre trial, USA, January 2004 to January 2006 Sample size: Number randomised: 60 Number completed: 51 Primary/secondary therapy: primary therapy Participant (baseline) characteristics: age/sex (male, female)/hearing loss at start of therapy/start of treatment/baseline SDS: Group I (intratympanic): 60 y/m,f not reported/82 ± 28 dB HL/11 ± 14 d/24 ± 38% Group II (combined): 57 y/m,f not reported/75 ± 23 dB HL/4 ± 3 d/41 ± 40% Group III (systemic): 54 y/m,f not reported/80 ± 27 dB HL/7 ± 6 d/34 ± 40% Inclusion criteria: ISSNHL within 6 weeks after onset. Patients with no identifiable cause of sudden hearing loss were considered to have ISSNHL. Exclusion criteria: diagnosis not ISSNHL, pregnancy, receiving previous treatment, Ménière's disease, autoimmune hearing loss, acoustic neuroma or other retrocochlear lesions. History of hearing fluctuation, recent ear infection, surgery or hospitalisation, exposure to ototoxins, trauma, drainage, tinnitus, pain, vertigo or family history of hearing loss. Medical conditions associated with sudden hearing loss such as diabetes, syphilis, chronic renal disease and cardiovascular disease.
Interventions	General comparison: intratympanic versus combined versus systemic corticosteroid therapy Intervention group I (n = 17*): "intratympanic therapy": placebo oral + intratympanic injection of dexamethasone, 12 mg/mL, 0.5 to 0.7 mL, 20 min, 3 injections total, 1x per week Intervention group II (n = 16*): "combined therapy": intratympanic injection + oral as in intervention group I and comparator group Comparator group (n = 18*): "systemic therapy": oral 60 mg prednisone with 10 mg taper every 2 days + intratympanic NaCl 0.9% (intratympanic placebo), 3 injections total, 1x per week Use of additional interventions (common to all treatment arms): none *modified intention‐to‐treat analysis
Outcomes	Primary outcome measure: Change in hearing threshold with pure tone audiometry Secondary outcomes: Proportion of patients whose hearing is improved (criterion of improvement > 15 dB decrease in PTA or > 25% in SDS) and change in hearing threshold with speech audiometry Adverse events Primary endpoint for hearing threshold evaluation: 43 days Used PTA: 3PTA (0.5, 1, 2 kHz)
Funding sources	No information available
Declarations of interest	No information provided
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "patients were randomized to 1 of 3 groups and administered treatment in double‐blinded fashion" Method of random sequence generation is not described.
Allocation concealment (selection bias)	Unclear risk	Method of concealment is not described.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "administered treatment in double‐blinded fashion".
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not mentioned but placebo‐controlled, double‐blind study design.
Incomplete outcome data (attrition bias) All outcomes	High risk	Rate of reported missing outcome data more than 10% (15%).
Selective reporting (reporting bias)	High risk	Missing standard deviation in reporting of hearing improvement.
Other bias	High risk	Recruitment of patients was terminated before number of patients from sample size calculation was reached. Wide range of treatment delay from onset in inclusion criteria. Difference in treatment delay from onset between groups.