N -Acetylcysteine combined with prednisolone treatment shows better hearing outcome than treatment with prednisolone alone for patients with idiopathic sudden sensorineural hearing loss: a retrospective observational study

Objectives: Internationally, corticosteroids are still the mainstay treatment for patients with idiopathic sudden sensorineural hearing loss (ISSHL). This is a retrospective monocentric study investing the impact of adding N -acetylcysteine (NAC) to prednisolone treatment on patients with ISSHL at a tertiary university otorhinolaryngology department. Methods: 793 patients (median age 60 years; 50.9% women) with a new diagnosis of ISSHL from 2009 to 2015 were included in the study. 663 patients received NAC administration in addition to standard tapered prednisolone treatment. Univariate and multivariable analysis were performed to identify independent factors regarding negative prognosis of hearing recovery. Results: Mean initial ISSHL and hearing gain after treatment in 10-tone pure tone audiometry (PTA) were 54.8 ± 34.5 dB and 15.2 ± 21.2 dB, respectively. In univariate analysis, treatment with prednisolone and NAC was associated with a positive prognosis of hearing recovery in the Japan classification in 10-tone PTA. In multivariable analysis on Japan classification in 10-tone PTA including all significant factors from univariate analysis, negative prognosis of hearing recovery were age > median (odds ratio [OR] 1.648; 95% confidence interval [CI] 1.139–2.385; p = 0.008), diseased opposite ear (OR 3.049; CI 2.157–4.310; p < 0.001), pantonal ISSHL (OR 1.891; CI 1.309–2.732; p = 0.001) and prednisolone alone without NAC treatment (OR 1.862; CI 1.200–2.887; p = 0.005). Conclusions: Prednisolone treatment combined with NAC resulted in better hearing outcomes in patients with ISSHL than treatment without NAC.