Al‐Shehri 2015.

Study characteristics
Methods	Non‐blinded, parallel‐group, randomised controlled trial with 14 days duration of treatment and 2‐month duration of follow‐up
Participants	Setting: tertiary referral centre, Saudi Arabia, January 2011 to December 2014 Sample size: Number randomised: 39 Number completed: 39 Primary/secondary therapy: primary therapy Participant (baseline) characteristics: age/sex (male, female)/hearing loss at start of therapy/start of treatment: Group I (intratympanic): 49.8 ± 5.9 y/9 m, 10 f/71.3 ± 5.9* dB HL/not reported Group II (systemic): 49.7 ± 7.3 y/9 m, 11 f/71.3 ± 6.9* dB HL/not reported * not clarified whether this is SD or SEM Inclusion criteria: age > 18, unilateral sensorineural hearing loss that developed within 72 hours and was present for 2 weeks or less. Patients' pure tone average (PTA) must have been 50 dB or higher, and the affected ear must have been at least 30 dB worse than the contralateral ear in at least 1 of the 4 PTA frequencies (i.e. 500, 1000, 2000 and 4000 Hz). Exclusion criteria: hearing has been asymmetric prior to the onset of ISSNHL. Pre‐enrollment steroid usage, previous history of hearing loss, Ménière's disease, or any chronic inflammatory or suppurative ear disease or cholesteatoma, otosclerosis, ear surgery (except ventilating tubes), hearing asymmetry prior to onset, congenital hearing loss, physical trauma or barotrauma to the ear immediately preceding hearing loss, history of genetic hearing loss with strong family history, or craniofacial or temporal bone malformations.
Interventions	General comparison: intratympanic versus systemic corticosteroid therapy Intervention group (n = 19*): "intratympanic therapy": intratympanic methylprednisolone sodium succinate 4 x 1 mL doses of 40 mg/mL over 2 weeks, with a dose given every 3 to 4 days Comparator group (n = 20*): "systemic therapy": oral prednisone 60 mg/d tapering over 14 days Use of additional interventions (common to both treatment arms): none *intention‐to‐treat analysis
Outcomes	Primary outcome measure: Change in hearing threshold with pure tone audiometry Secondary outcomes: Adverse events Primary endpoint for hearing threshold evaluation: 75 days Used PTA: 4PTA (0.5, 1, 2, 4 kHz)
Funding sources	No information available
Declarations of interest	None declared
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "[Patients] were consecutively randomized" 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	Open‐label trial, no blinding.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The researcher was not blinded to the treatment group but the audiologists were blinded to it."
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data reported.
Selective reporting (reporting bias)	Low risk	No indication of selective reporting in the outcome parameters addressed by the review.
Other bias	High risk	No sample size calculation performed. Treatment delay from onset in patients not reported. Single authorship generally exhibits a certain risk of bias. Completely equal baseline PTA is notable.