Characteristics and prognosis analysis of bilateral sudden sensorineural hearing loss: A retrospective case-control study.

Abstract

To evaluate the clinical characteristics and prognostic factors of simultaneous and sequential bilateral sudden sensorineural hearing loss (Si-BSSNHL and Se-BSSNHL, respectively). Retrospective case-control study. A single tertiary referral centre. Patients diagnosed with unilateral sudden sensorineural hearing loss (USSNHL), Si-BSSNHL, or Se-BSSNHL between September 2018 and November 2019. Demographic and clinical characteristics, audiological features, laboratory results and hearing recovery were analysed for intergroup comparisons. Prognostic factors for BSSNHL were analysed using univariate and multivariate logistic analyses between the overall and no-recovery groups. Compared to the USSNHL group, a larger final pure-tone average (PTA) (H=38.0 and 53.8, respectively, both adjusted p-value (p adj) <.05), lower hearing gain (H=-70.8 and - 74.6, respectively, both p adj <.001) and higher homocysteine levels (H=46.8, 58.8, respectively, both p adj <.05) were observed in the Si-BSSNHL and Se-BSSNHL groups, while the rate of positive vestibular tests and proportion of tinnitus were lower in the Se-BSSNHL group (χ2 =8.5 and 38.1, respectively, both p adj <0.05). The USSNHL group showed a significant difference in the degree of deafness and therapeutic outcome in the Se-BSSNHL and Si-BSSNHL groups, respectively (χ2 =12.4, p adj <.05; χ2 =13.6; p adj <.05). Hypertension (95% confidence interval, 1.014-28.623, p < .05) and onset days (95% confidence interval, 0.007-0.626, p < .05) were associated with the therapeutic effects of BSSNHL. Higher homocysteine levels in BSSNHL may implicate microvascular disorders as a causative factor of BSSNHL. Hypertension and onset days were associated with the prognosis of BSSNHL.