Quality assessment of studies included to assess the effect of NAC on aminoglycoside-induced ototoxicity
| Feldman, 200714 | ||
| Methods | Randomised, open-label, controlled, parallel, one centre, duration 50 days, intention to treat analysis | |
| Participants | 53 patients aged 18+ on haemodialysis treated with gentamicin for dialysis catheter-related bacteraemia, excluded if treated with aminoglycosides 3 months before the episode or mechanical occlusion of the external ear or a perforated tympanic membrane | |
| Interventions | NAC 600 mg twice daily | |
| Outcomes | Pure-tone audiometry measurements at frequencies 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12 000 Hz at 7±3 and 42±3 days after completion of gentamicin therapy | |
| Bias | Author's judgement | Support for judgement |
| Random sequence generation | Unclear | |
| Allocation concealment | High risk | No placebo |
| Blinding of participants and personnel | High risk | No placebo |
| Incomplete outcome data | Low risk | |
| Selective reporting | Unclear | Primary outcomes not specifically reported, no protocol available |
| Other bias | Low risk | |
| Tokgoz, 201116 | ||
| Methods | Randomised, open-label, controlled, parallel, one centre, duration 28 days, analysis (per protocol or intention to treat) not clarified | |
| Participants | 60 patients on peritoneal dialysis treated with amikacin for their first episode of peritonitis, excluded if tympanic membrane perforated and admitted after office hours | |
| Interventions | NAC 600 mg twice daily | |
| Outcomes | Pure-tone audiometry measurements at frequencies 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 10 000, 12 000, 14 000 and 16 000 Hz at 8±2 days and 28±2 days | |
| Bias | Author's judgement | Support for judgement |
| Random sequence generation | Low risk | Patients chose an envelop |
| Allocation concealment | High risk | No placebo |
| Blinding of participants and personnel | High risk | No placebo |
| Incomplete outcome data | Low risk | |
| Selective reporting | Unclear | Primary outcomes not specifically reported, no protocol available |
| Other bias | Low risk | |
| Kocyigit, 201417 | ||
| Methods | Randomised, placebo controlled, parallel, one centre, duration 28 days, analysis (per protocol or intention to treat) not clarified | |
| Participants | 46 patients on peritoneal dialysis treated with amikacin for their first episode of peritonitis, excluded if tympanic membrane perforated and admitted after office hours | |
| Interventions | NAC 600 mg twice daily or placebo | |
| Outcomes | Transient-evoked otoacoustic emissions and distortion-product otoacoustic emissions at 1 and 4 weeks | |
| Bias | Author's judgement | Support for judgement |
| Random sequence generation | Low risk | Patients chose an envelop |
| Allocation concealment | Low risk | Placebo administered |
| Blinding of participants and personnel | Low risk | Measurements of patients were performed by staff who did not know which patient belonged to which group |
| Incomplete outcome data | Low risk | |
| Selective reporting | Unclear | Primary outcomes not specifically reported, no protocol available |
| Other bias | Low risk | |
NAC, N-acetylcysteine.