Prognostic impact of standard laboratory values on outcome in patients with sudden sensorineural hearing loss

Aim of the present study was to evaluate prognostic factors, in particular standard laboratory parameters, for better outcome after idiopathic sudden sensorineural hearing loss (SSNHL).

Using a retrospective review, 173 patients were included presenting between 2006 and 2009 with unilateral SSNHL, ≥30 dB bone conduction in three succeeding frequencies between 0.125 to 8 kHz in pure tone audiometry (PTA), and a time interval between first symptoms and diagnostics ≤ 4 weeks. Hearing gain of <10 dB versus ≥10 dB in the affected ear in 6PTA values was the primary outcome criterion. Univariate and multivariate statistical tests were used to analyze predictors for better outcome.

The initial hearing loss was 50.6 ± 27.2 dB. The absolute hearing gain was 15.6 ± 20.1 dB. Eighty-one patients (47%) had a final hearing gain of ≥10 dB. Low-frequency hearing loss (p <0.0001); start of inpatient treatment <4 days after onset (p = 0.018); first SSNHL (versus recurrent SSNHL, p = 0.001); initial hearing loss ≥ 60 dB (p < 0.0001); an initial quick value lower than the reference values (p = 0.040); and a pretherapeutic hyperfibrinogenemia (p = 0.007) were significantly correlated to better outcome (≥10 dB absolute hearing gain). Multivariate analysis revealed that first SSNHL (p = 0.004), start of treatment <4 days after onset (p = 0.015), initial hearing loss ≥ 60 dB (p = 0.001), and hyperfibrinogenemia (p = 0.032) were independent prognostic factors for better hearing recovery.

Better hearing gain in patients with hyperfibrinogenemia might be explained by the rheological properties of the applied therapy and supports the hypothesis that SSNHL is caused in part by vascular factors.